[1] Rectifiers are used to convert -
A.
Direct current to Alternating current
B.
Alternating current to Direct current
C.
high voltage to low voltage
D.
low voltage to high voltage
Ans:
Alternating current to Direct current
Explanation :
Converting DC power from one voltage to another is much more complicated. One method of DC -to-DC conversion first converts power to AC (using a device called an inverter), then uses a transformer to change the voltage, and finally rectifies power back to DC.
[2] A dynamo is used to convert –
A.
mechanical energy into electrical energy
B.
electrical energy into mechanical energy
C.
electrical energy into magnetic energy
D.
magnetic energy into mechanical energy
Ans:
mechanical energy into electrical energy
Explanation :
A dynamo converts mechanical energy into electrical energy by taking advantage of a phenomenon known as electromagnetic induction. It is an electric generator that is similar to those that provide electricity to our homes.
[3] Absolute Zero is defined as –
A.
The temperature at which all molecular motion ceases
B.
At which water boils at 298K
C.
At which liquid Helium boils
D.
At which the volume becomes zero
Ans:
The temperature at which all molecular motion ceases
Explanation :
Absolute zero is the temperature at which all motion in matter stops and is thought to be unreachable. It is the point at which the fundamental particles of nature have minimal vibrational motion, retaining only quantum mechanical, zero-point energy-induced particle motion.
[4] When a ring of metal is heated what happens to its hole?
A.
expands
B.
contracts
C.
it expands or contracts according to its diameter
D.
it expands or contracts according to its coefficient of expansion
Ans:
expands
Explanation :
The hole size will increase because in expansion the size between two molecules, do not increase so when the molecules on the outer edge move outward. Due to expansion, the size of the hole will also increase so as to compensate the distance change between the molecules. Thermal expansion is the tendency of matter to change in volume in response to a change in temperature.
[5] Red is used as an emergency or danger signal as –
A.
it is a striking colour
B.
its wavelength is the longest
C.
it is scattered
D.
it has very high energy
Ans:
its wavelength is the longest
Explanation :
The effect of scattering is inversely related to the fourth power of the wavelength of a colour. Red has the highest wavelength of all the colours and is able to travel the longest distance through fog, rain, and the alike.
[6] The dynamo converts –
A.
mechanical energy into electrical energy
B.
electrical energy into mechanical energy
C.
mechanical energy into magnetic energy
D.
magnetic energy into mechanical energy
Ans:
mechanical energy into electrical energy
Explanation :
Dynamo is a device for converting mechanical energy into electrical energy, especially one that produces direct current. It uses electromagnetic principles to convert mechanical rotation into a pulsing direct electric current through the use of a commutator.
[7] A small drop of oil spreads over water because :
A.
oil has a higher surface tension
B.
water has a higher surface tension
C.
oil has a higher viscosity
D.
water has a higher viscosity
Ans:
water has a higher surface tension
Explanation :
Dispersion is used to separate a beam of white light into its constituent spectrum of colours. This phenomenon leads to rainbow.
[8] A small gap is left at the joints of rails in a railway track to –
A.
avoid the tracks being distorted due to seasonal temperature variation
B.
avoid the heating of tracks to high temperature
C.
control the speed of train
D.
keep the rails equidistant
Ans:
avoid the tracks being distorted due to seasonal temperature variation
Explanation :
A small gap is left at the joints of rails in a railway track to provide space for the expansion of rai l pieces when the temperature rises during summer.
[9] Which of the following criterion is used for any metal to be used as a cooking material?
A.
More specific heat
B.
More thermal conductivity
C.
Less thermal conductivity
D.
Less electrical conductivity
Ans:
Less thermal conductivity
Explanation :
A metal to be used as a cooking material should have less thermal conductivity.
[10] Super conductors are substances that –
A.
offer minimum resistance to flow of electric current
B.
conduct electricity at low temperature
C.
conduct electricity at high temperature
D.
offer high resistance to the flow of electric current
Ans:
offer minimum resistance to flow of electric current
Explanation :
A superconductor is a material that can conduct electricity or transport electrons from one atom to another with no resistance. No heat, sound or any other form of energy is released from the material when it reaches the temperature at which it becomes superconductive.
[11] Cloudy nights are wanner compared nights, because clouds mainly –
A.
Absorb heat from the atmosphere send it towards earth
B.
Prevent cold waves from the sky descending on earth
C.
Reflect back the heat given by earth
D.
Produce heat and radiate it toward earth
Ans:
Reflect back the heat given by earth
Explanation :
It is because the night side of Earth will radiate infra-red radiation (heat) back into space. When there is cloud cover, the clouds act like a blanket and trap the heat close to the ground just like a blanket traps heat close to our body.
[12] Kepler's law of planetary motion states that the square of the time period is proportional to the –
A.
semi-major axis
B.
square of the semi-major axis
C.
cube of the semi-major axis
D.
fourth power of the serni-major axis
Ans:
cube of the semi-major axis
Explanation :
Kepler's law of planetary motion states that the square of the time period is proportional to the cube of the semi-major axis.
[13] Spring tides occur when:
A.
the moon, the sun and the earth are in the same line
B.
the sun is closest to earth
C.
the moon is farthest from earth
D.
the earth is at right angles with the sun and the moon
Ans:
the moon, the sun and the earth are in the same line
Explanation :
The combined tide raising forces of the Moon and the Sun are at their greatest effect when the Sun and the Moon are in line with the Earth.
[14] When a ship enters the sea from a river –
A.
It rises a little
B.
It sinks a little
C.
It remains at the same level
D.
It rises or sinks depending on the material it is made of
Ans:
It rises a little
Explanation :
On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, or 599 mM). Seawater is denser than hot fresh water and pure water (density 1.0 g/ml) because the dissolved salts add mass without contributing significantly to the volume.
[15] Why are we able to hear short wave broadcasts better than long wave broadcasts?
A.
Short waves are more energetic than long waves
B.
Short waves are unaffected by atmospheric disturbances
C.
Short wave broadcasts are made by nearby radio stations
D.
By convention, short waves are meant for long distances, whereas long waves are reserved for short distances
Ans:
Short waves are more energetic than long waves
Explanation :
Shortwave radio is used for broadcasting of voice and music, and long-distance communication to ships and aircraft, or to remote areas out of reach of wired communication or other radio services and that's why it is more energetic than long waves.
[16] In severe winter, in cold countries water pipes burst because –
A.
Water expands on freezing
B.
Contraction of water pipes
C.
High atmospheric pressure
D.
Combined effect of all the above three
Ans:
Water expands on freezing
Explanation :
Most liquids have a quite simple behavior when they are cooled (at a fixed pressure): they shrink. The liquid contract as it is cooled; because the molecules are moving slower they are less able to overcome the attractive intermolecular forces drawing them closer to each other. Then the freezing temperature is reached, and the substance solidifies, which causes it to contract some more because crystalline solids are usually tightly packed.
[17] A television channel is characterized by –
A.
frequency of transmitted signal
B.
velocity of transmitted signal
C.
physical dimension of television screen
D.
size of picture tube
Ans:
frequency of transmitted signal
Explanation :
A television channel is a physical or virtual channel over which a television station or television network is distributed. Channel numbers represent actual frequencies used to broadcast the television signal. For example, in North America, "channel 2" refers to the broadcast or cable band of 54 to 60 MHz, with carrier frequencies of 55.25 MHz for NTSC analog video (VSB) and 59.75 MHz for analog audio (FM), or 55.31 MHz for digital ATSC (8VSB).
[18] Which one of the following not a feature of Indifference Curve?
A.
They do not intersect each other
B.
They slope downwards to the right
C.
They are parallel to each other
D.
They are concave to each other
Ans:
They are concave to each other
Explanation :
Indifference curves are usually convex to the origin. In other words, the indifference curve is relatively flatter in its right-hand portion and relatively steeper in its left-hand portion. The degree of convexity of an indifference curve depends on the rate of fall in the marginal rate of substitution.
[19] Heat energy of an object is -
A.
The average energy of the molecules of the object
B.
The total energy of the molecules of the object
C.
The average velocity of the molecules of the object
D.
The average P.E. of the molecules of the object
Ans:
The total energy of the molecules of the object
Explanation :
The transfer or flow due to the difference in temperature between the two objects is called heat. Heat energy of an object is the total energy of the molecules of the object.
[20] If a body moves with a constant speed in a circle –
A.
no work is done on it
B.
no force acts on it
C.
no acceleration is produced in it
D.
its velocity remains constant
Ans:
its velocity remains constant
Explanation :
A body moving with a constant speed in a circle is an example of uniform circular motion. The velocity vector is constant in magnitude but changing in direction. Since velocity is a vector quantity that has both magnitude and direction, a change in either the magnitude or the direction constitutes a change in the velocity which leads to change in acceleration.
[21] A white and smooth surface is –
A.
good absorber and good reflector of heat
B.
bad absorber and good reflector of heat
C.
good absorber and bad reflector of heat
D.
bad absorber and bad reflector of heat
Ans:
bad absorber and good reflector of heat
Explanation :
Shiny surfaces are poor absorbers of heat radiation and the best reflectors of heat radiation. Black surfaces are the best emitters and best absorber of heat radiation.
[22] It is easier for a man to swim in sea water, than in river water because –
A.
the density of sea water is lesser than the density of river water
B.
the density of sea water is more than the density of river water
C.
the sea is deeper than the river
D.
the sea is wider than the river
Ans:
the density of sea water is more than the density of river water
Explanation :
the density of sea water is more than the density of river water
[23] In the pressure cooker, cooking is faster because the increase in vapour pressure -
A.
increase the specific heat
B.
decreases the specific heat
C.
decreases the boiling point
D.
increases the boiling point
Ans:
increases the boiling point
Explanation :
0
[24] Kinetic energy depends on –
A.
the velocity or speed of the moving body.
B.
the mass of the moving body
C.
the pressure of the moving body
D.
both mass and velocity of the moving body
Ans:
both mass and velocity of the moving body
Explanation :
Kinetic energy is the energy associated with the movement of objects. The amount of kinetic energy that an object has depends upon two variables: the mass (m) of the object and the speed (v) of the object.
[25] The apparent weight of a man in a lift is less the real weight when –
A.
the lift is going up with an acceleration
B.
the lift is going down with uniform speed
C.
the lift is going up with uniform speed
D.
the lift is going down with an acceleration
Ans:
the lift is going down with an acceleration
Explanation :
If the lift accelerates downwards with acceleration a, then the apparent weight of the man standing in the lift will be less than the true weight of the man by an amount ma. On the contrary, if the lift accelerates upwards with acceleration, then the apparent weight of the man will be greater than his true weight.
Explanation :
Converting DC power from one voltage to another is much more complicated. One method of DC -to-DC conversion first converts power to AC (using a device called an inverter), then uses a transformer to change the voltage, and finally rectifies power back to DC.
[2] A dynamo is used to convert –
A.
mechanical energy into electrical energy
B.
electrical energy into mechanical energy
C.
electrical energy into magnetic energy
D.
magnetic energy into mechanical energy
Ans:
mechanical energy into electrical energy
Explanation :
A dynamo converts mechanical energy into electrical energy by taking advantage of a phenomenon known as electromagnetic induction. It is an electric generator that is similar to those that provide electricity to our homes.
[3] Absolute Zero is defined as –
A.
The temperature at which all molecular motion ceases
B.
At which water boils at 298K
C.
At which liquid Helium boils
D.
At which the volume becomes zero
Ans:
The temperature at which all molecular motion ceases
Explanation :
Absolute zero is the temperature at which all motion in matter stops and is thought to be unreachable. It is the point at which the fundamental particles of nature have minimal vibrational motion, retaining only quantum mechanical, zero-point energy-induced particle motion.
[4] When a ring of metal is heated what happens to its hole?
A.
expands
B.
contracts
C.
it expands or contracts according to its diameter
D.
it expands or contracts according to its coefficient of expansion
Ans:
expands
Explanation :
The hole size will increase because in expansion the size between two molecules, do not increase so when the molecules on the outer edge move outward. Due to expansion, the size of the hole will also increase so as to compensate the distance change between the molecules. Thermal expansion is the tendency of matter to change in volume in response to a change in temperature.
[5] Red is used as an emergency or danger signal as –
A.
it is a striking colour
B.
its wavelength is the longest
C.
it is scattered
D.
it has very high energy
Ans:
its wavelength is the longest
Explanation :
The effect of scattering is inversely related to the fourth power of the wavelength of a colour. Red has the highest wavelength of all the colours and is able to travel the longest distance through fog, rain, and the alike.
[6] The dynamo converts –
A.
mechanical energy into electrical energy
B.
electrical energy into mechanical energy
C.
mechanical energy into magnetic energy
D.
magnetic energy into mechanical energy
Ans:
mechanical energy into electrical energy
Explanation :
Dynamo is a device for converting mechanical energy into electrical energy, especially one that produces direct current. It uses electromagnetic principles to convert mechanical rotation into a pulsing direct electric current through the use of a commutator.
[7] A small drop of oil spreads over water because :
A.
oil has a higher surface tension
B.
water has a higher surface tension
C.
oil has a higher viscosity
D.
water has a higher viscosity
Ans:
water has a higher surface tension
Explanation :
Dispersion is used to separate a beam of white light into its constituent spectrum of colours. This phenomenon leads to rainbow.
[8] A small gap is left at the joints of rails in a railway track to –
A.
avoid the tracks being distorted due to seasonal temperature variation
B.
avoid the heating of tracks to high temperature
C.
control the speed of train
D.
keep the rails equidistant
Ans:
avoid the tracks being distorted due to seasonal temperature variation
Explanation :
A small gap is left at the joints of rails in a railway track to provide space for the expansion of rai l pieces when the temperature rises during summer.
[9] Which of the following criterion is used for any metal to be used as a cooking material?
A.
More specific heat
B.
More thermal conductivity
C.
Less thermal conductivity
D.
Less electrical conductivity
Ans:
Less thermal conductivity
Explanation :
A metal to be used as a cooking material should have less thermal conductivity.
[10] Super conductors are substances that –
A.
offer minimum resistance to flow of electric current
B.
conduct electricity at low temperature
C.
conduct electricity at high temperature
D.
offer high resistance to the flow of electric current
Ans:
offer minimum resistance to flow of electric current
Explanation :
A superconductor is a material that can conduct electricity or transport electrons from one atom to another with no resistance. No heat, sound or any other form of energy is released from the material when it reaches the temperature at which it becomes superconductive.
[11] Cloudy nights are wanner compared nights, because clouds mainly –
A.
Absorb heat from the atmosphere send it towards earth
B.
Prevent cold waves from the sky descending on earth
C.
Reflect back the heat given by earth
D.
Produce heat and radiate it toward earth
Ans:
Reflect back the heat given by earth
Explanation :
It is because the night side of Earth will radiate infra-red radiation (heat) back into space. When there is cloud cover, the clouds act like a blanket and trap the heat close to the ground just like a blanket traps heat close to our body.
[12] Kepler's law of planetary motion states that the square of the time period is proportional to the –
A.
semi-major axis
B.
square of the semi-major axis
C.
cube of the semi-major axis
D.
fourth power of the serni-major axis
Ans:
cube of the semi-major axis
Explanation :
Kepler's law of planetary motion states that the square of the time period is proportional to the cube of the semi-major axis.
[13] Spring tides occur when:
A.
the moon, the sun and the earth are in the same line
B.
the sun is closest to earth
C.
the moon is farthest from earth
D.
the earth is at right angles with the sun and the moon
Ans:
the moon, the sun and the earth are in the same line
Explanation :
The combined tide raising forces of the Moon and the Sun are at their greatest effect when the Sun and the Moon are in line with the Earth.
[14] When a ship enters the sea from a river –
A.
It rises a little
B.
It sinks a little
C.
It remains at the same level
D.
It rises or sinks depending on the material it is made of
Ans:
It rises a little
Explanation :
On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, or 599 mM). Seawater is denser than hot fresh water and pure water (density 1.0 g/ml) because the dissolved salts add mass without contributing significantly to the volume.
[15] Why are we able to hear short wave broadcasts better than long wave broadcasts?
A.
Short waves are more energetic than long waves
B.
Short waves are unaffected by atmospheric disturbances
C.
Short wave broadcasts are made by nearby radio stations
D.
By convention, short waves are meant for long distances, whereas long waves are reserved for short distances
Ans:
Short waves are more energetic than long waves
Explanation :
Shortwave radio is used for broadcasting of voice and music, and long-distance communication to ships and aircraft, or to remote areas out of reach of wired communication or other radio services and that's why it is more energetic than long waves.
[16] In severe winter, in cold countries water pipes burst because –
A.
Water expands on freezing
B.
Contraction of water pipes
C.
High atmospheric pressure
D.
Combined effect of all the above three
Ans:
Water expands on freezing
Explanation :
Most liquids have a quite simple behavior when they are cooled (at a fixed pressure): they shrink. The liquid contract as it is cooled; because the molecules are moving slower they are less able to overcome the attractive intermolecular forces drawing them closer to each other. Then the freezing temperature is reached, and the substance solidifies, which causes it to contract some more because crystalline solids are usually tightly packed.
[17] A television channel is characterized by –
A.
frequency of transmitted signal
B.
velocity of transmitted signal
C.
physical dimension of television screen
D.
size of picture tube
Ans:
frequency of transmitted signal
Explanation :
A television channel is a physical or virtual channel over which a television station or television network is distributed. Channel numbers represent actual frequencies used to broadcast the television signal. For example, in North America, "channel 2" refers to the broadcast or cable band of 54 to 60 MHz, with carrier frequencies of 55.25 MHz for NTSC analog video (VSB) and 59.75 MHz for analog audio (FM), or 55.31 MHz for digital ATSC (8VSB).
[18] Which one of the following not a feature of Indifference Curve?
A.
They do not intersect each other
B.
They slope downwards to the right
C.
They are parallel to each other
D.
They are concave to each other
Ans:
They are concave to each other
Explanation :
Indifference curves are usually convex to the origin. In other words, the indifference curve is relatively flatter in its right-hand portion and relatively steeper in its left-hand portion. The degree of convexity of an indifference curve depends on the rate of fall in the marginal rate of substitution.
[19] Heat energy of an object is -
A.
The average energy of the molecules of the object
B.
The total energy of the molecules of the object
C.
The average velocity of the molecules of the object
D.
The average P.E. of the molecules of the object
Ans:
The total energy of the molecules of the object
Explanation :
The transfer or flow due to the difference in temperature between the two objects is called heat. Heat energy of an object is the total energy of the molecules of the object.
[20] If a body moves with a constant speed in a circle –
A.
no work is done on it
B.
no force acts on it
C.
no acceleration is produced in it
D.
its velocity remains constant
Ans:
its velocity remains constant
Explanation :
A body moving with a constant speed in a circle is an example of uniform circular motion. The velocity vector is constant in magnitude but changing in direction. Since velocity is a vector quantity that has both magnitude and direction, a change in either the magnitude or the direction constitutes a change in the velocity which leads to change in acceleration.
[21] A white and smooth surface is –
A.
good absorber and good reflector of heat
B.
bad absorber and good reflector of heat
C.
good absorber and bad reflector of heat
D.
bad absorber and bad reflector of heat
Ans:
bad absorber and good reflector of heat
Explanation :
Shiny surfaces are poor absorbers of heat radiation and the best reflectors of heat radiation. Black surfaces are the best emitters and best absorber of heat radiation.
[22] It is easier for a man to swim in sea water, than in river water because –
A.
the density of sea water is lesser than the density of river water
B.
the density of sea water is more than the density of river water
C.
the sea is deeper than the river
D.
the sea is wider than the river
Ans:
the density of sea water is more than the density of river water
Explanation :
the density of sea water is more than the density of river water
[23] In the pressure cooker, cooking is faster because the increase in vapour pressure -
A.
increase the specific heat
B.
decreases the specific heat
C.
decreases the boiling point
D.
increases the boiling point
Ans:
increases the boiling point
Explanation :
0
[24] Kinetic energy depends on –
A.
the velocity or speed of the moving body.
B.
the mass of the moving body
C.
the pressure of the moving body
D.
both mass and velocity of the moving body
Ans:
both mass and velocity of the moving body
Explanation :
Kinetic energy is the energy associated with the movement of objects. The amount of kinetic energy that an object has depends upon two variables: the mass (m) of the object and the speed (v) of the object.
[25] The apparent weight of a man in a lift is less the real weight when –
A.
the lift is going up with an acceleration
B.
the lift is going down with uniform speed
C.
the lift is going up with uniform speed
D.
the lift is going down with an acceleration
Ans:
the lift is going down with an acceleration
Explanation :
If the lift accelerates downwards with acceleration a, then the apparent weight of the man standing in the lift will be less than the true weight of the man by an amount ma. On the contrary, if the lift accelerates upwards with acceleration, then the apparent weight of the man will be greater than his true weight.
Explanation :
Absolute zero is the temperature at which all motion in matter stops and is thought to be unreachable. It is the point at which the fundamental particles of nature have minimal vibrational motion, retaining only quantum mechanical, zero-point energy-induced particle motion.
[4] When a ring of metal is heated what happens to its hole?
A.
expands
B.
contracts
C.
it expands or contracts according to its diameter
D.
it expands or contracts according to its coefficient of expansion
Ans:
expands
Explanation :
The hole size will increase because in expansion the size between two molecules, do not increase so when the molecules on the outer edge move outward. Due to expansion, the size of the hole will also increase so as to compensate the distance change between the molecules. Thermal expansion is the tendency of matter to change in volume in response to a change in temperature.
[5] Red is used as an emergency or danger signal as –
A.
it is a striking colour
B.
its wavelength is the longest
C.
it is scattered
D.
it has very high energy
Ans:
its wavelength is the longest
Explanation :
The effect of scattering is inversely related to the fourth power of the wavelength of a colour. Red has the highest wavelength of all the colours and is able to travel the longest distance through fog, rain, and the alike.
[6] The dynamo converts –
A.
mechanical energy into electrical energy
B.
electrical energy into mechanical energy
C.
mechanical energy into magnetic energy
D.
magnetic energy into mechanical energy
Ans:
mechanical energy into electrical energy
Explanation :
Dynamo is a device for converting mechanical energy into electrical energy, especially one that produces direct current. It uses electromagnetic principles to convert mechanical rotation into a pulsing direct electric current through the use of a commutator.
[7] A small drop of oil spreads over water because :
A.
oil has a higher surface tension
B.
water has a higher surface tension
C.
oil has a higher viscosity
D.
water has a higher viscosity
Ans:
water has a higher surface tension
Explanation :
Dispersion is used to separate a beam of white light into its constituent spectrum of colours. This phenomenon leads to rainbow.
[8] A small gap is left at the joints of rails in a railway track to –
A.
avoid the tracks being distorted due to seasonal temperature variation
B.
avoid the heating of tracks to high temperature
C.
control the speed of train
D.
keep the rails equidistant
Ans:
avoid the tracks being distorted due to seasonal temperature variation
Explanation :
A small gap is left at the joints of rails in a railway track to provide space for the expansion of rai l pieces when the temperature rises during summer.
[9] Which of the following criterion is used for any metal to be used as a cooking material?
A.
More specific heat
B.
More thermal conductivity
C.
Less thermal conductivity
D.
Less electrical conductivity
Ans:
Less thermal conductivity
Explanation :
A metal to be used as a cooking material should have less thermal conductivity.
[10] Super conductors are substances that –
A.
offer minimum resistance to flow of electric current
B.
conduct electricity at low temperature
C.
conduct electricity at high temperature
D.
offer high resistance to the flow of electric current
Ans:
offer minimum resistance to flow of electric current
Explanation :
A superconductor is a material that can conduct electricity or transport electrons from one atom to another with no resistance. No heat, sound or any other form of energy is released from the material when it reaches the temperature at which it becomes superconductive.
[11] Cloudy nights are wanner compared nights, because clouds mainly –
A.
Absorb heat from the atmosphere send it towards earth
B.
Prevent cold waves from the sky descending on earth
C.
Reflect back the heat given by earth
D.
Produce heat and radiate it toward earth
Ans:
Reflect back the heat given by earth
Explanation :
It is because the night side of Earth will radiate infra-red radiation (heat) back into space. When there is cloud cover, the clouds act like a blanket and trap the heat close to the ground just like a blanket traps heat close to our body.
[12] Kepler's law of planetary motion states that the square of the time period is proportional to the –
A.
semi-major axis
B.
square of the semi-major axis
C.
cube of the semi-major axis
D.
fourth power of the serni-major axis
Ans:
cube of the semi-major axis
Explanation :
Kepler's law of planetary motion states that the square of the time period is proportional to the cube of the semi-major axis.
[13] Spring tides occur when:
A.
the moon, the sun and the earth are in the same line
B.
the sun is closest to earth
C.
the moon is farthest from earth
D.
the earth is at right angles with the sun and the moon
Ans:
the moon, the sun and the earth are in the same line
Explanation :
The combined tide raising forces of the Moon and the Sun are at their greatest effect when the Sun and the Moon are in line with the Earth.
[14] When a ship enters the sea from a river –
A.
It rises a little
B.
It sinks a little
C.
It remains at the same level
D.
It rises or sinks depending on the material it is made of
Ans:
It rises a little
Explanation :
On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, or 599 mM). Seawater is denser than hot fresh water and pure water (density 1.0 g/ml) because the dissolved salts add mass without contributing significantly to the volume.
[15] Why are we able to hear short wave broadcasts better than long wave broadcasts?
A.
Short waves are more energetic than long waves
B.
Short waves are unaffected by atmospheric disturbances
C.
Short wave broadcasts are made by nearby radio stations
D.
By convention, short waves are meant for long distances, whereas long waves are reserved for short distances
Ans:
Short waves are more energetic than long waves
Explanation :
Shortwave radio is used for broadcasting of voice and music, and long-distance communication to ships and aircraft, or to remote areas out of reach of wired communication or other radio services and that's why it is more energetic than long waves.
[16] In severe winter, in cold countries water pipes burst because –
A.
Water expands on freezing
B.
Contraction of water pipes
C.
High atmospheric pressure
D.
Combined effect of all the above three
Ans:
Water expands on freezing
Explanation :
Most liquids have a quite simple behavior when they are cooled (at a fixed pressure): they shrink. The liquid contract as it is cooled; because the molecules are moving slower they are less able to overcome the attractive intermolecular forces drawing them closer to each other. Then the freezing temperature is reached, and the substance solidifies, which causes it to contract some more because crystalline solids are usually tightly packed.
[17] A television channel is characterized by –
A.
frequency of transmitted signal
B.
velocity of transmitted signal
C.
physical dimension of television screen
D.
size of picture tube
Ans:
frequency of transmitted signal
Explanation :
A television channel is a physical or virtual channel over which a television station or television network is distributed. Channel numbers represent actual frequencies used to broadcast the television signal. For example, in North America, "channel 2" refers to the broadcast or cable band of 54 to 60 MHz, with carrier frequencies of 55.25 MHz for NTSC analog video (VSB) and 59.75 MHz for analog audio (FM), or 55.31 MHz for digital ATSC (8VSB).
[18] Which one of the following not a feature of Indifference Curve?
A.
They do not intersect each other
B.
They slope downwards to the right
C.
They are parallel to each other
D.
They are concave to each other
Ans:
They are concave to each other
Explanation :
Indifference curves are usually convex to the origin. In other words, the indifference curve is relatively flatter in its right-hand portion and relatively steeper in its left-hand portion. The degree of convexity of an indifference curve depends on the rate of fall in the marginal rate of substitution.
[19] Heat energy of an object is -
A.
The average energy of the molecules of the object
B.
The total energy of the molecules of the object
C.
The average velocity of the molecules of the object
D.
The average P.E. of the molecules of the object
Ans:
The total energy of the molecules of the object
Explanation :
The transfer or flow due to the difference in temperature between the two objects is called heat. Heat energy of an object is the total energy of the molecules of the object.
[20] If a body moves with a constant speed in a circle –
A.
no work is done on it
B.
no force acts on it
C.
no acceleration is produced in it
D.
its velocity remains constant
Ans:
its velocity remains constant
Explanation :
A body moving with a constant speed in a circle is an example of uniform circular motion. The velocity vector is constant in magnitude but changing in direction. Since velocity is a vector quantity that has both magnitude and direction, a change in either the magnitude or the direction constitutes a change in the velocity which leads to change in acceleration.
[21] A white and smooth surface is –
A.
good absorber and good reflector of heat
B.
bad absorber and good reflector of heat
C.
good absorber and bad reflector of heat
D.
bad absorber and bad reflector of heat
Ans:
bad absorber and good reflector of heat
Explanation :
Shiny surfaces are poor absorbers of heat radiation and the best reflectors of heat radiation. Black surfaces are the best emitters and best absorber of heat radiation.
[22] It is easier for a man to swim in sea water, than in river water because –
A.
the density of sea water is lesser than the density of river water
B.
the density of sea water is more than the density of river water
C.
the sea is deeper than the river
D.
the sea is wider than the river
Ans:
the density of sea water is more than the density of river water
Explanation :
the density of sea water is more than the density of river water
[23] In the pressure cooker, cooking is faster because the increase in vapour pressure -
A.
increase the specific heat
B.
decreases the specific heat
C.
decreases the boiling point
D.
increases the boiling point
Ans:
increases the boiling point
Explanation :
0
[24] Kinetic energy depends on –
A.
the velocity or speed of the moving body.
B.
the mass of the moving body
C.
the pressure of the moving body
D.
both mass and velocity of the moving body
Ans:
both mass and velocity of the moving body
Explanation :
Kinetic energy is the energy associated with the movement of objects. The amount of kinetic energy that an object has depends upon two variables: the mass (m) of the object and the speed (v) of the object.
[25] The apparent weight of a man in a lift is less the real weight when –
A.
the lift is going up with an acceleration
B.
the lift is going down with uniform speed
C.
the lift is going up with uniform speed
D.
the lift is going down with an acceleration
Ans:
the lift is going down with an acceleration
Explanation :
If the lift accelerates downwards with acceleration a, then the apparent weight of the man standing in the lift will be less than the true weight of the man by an amount ma. On the contrary, if the lift accelerates upwards with acceleration, then the apparent weight of the man will be greater than his true weight.
Explanation :
The effect of scattering is inversely related to the fourth power of the wavelength of a colour. Red has the highest wavelength of all the colours and is able to travel the longest distance through fog, rain, and the alike.
[6] The dynamo converts –
A.
mechanical energy into electrical energy
B.
electrical energy into mechanical energy
C.
mechanical energy into magnetic energy
D.
magnetic energy into mechanical energy
Ans:
mechanical energy into electrical energy
Explanation :
Dynamo is a device for converting mechanical energy into electrical energy, especially one that produces direct current. It uses electromagnetic principles to convert mechanical rotation into a pulsing direct electric current through the use of a commutator.
[7] A small drop of oil spreads over water because :
A.
oil has a higher surface tension
B.
water has a higher surface tension
C.
oil has a higher viscosity
D.
water has a higher viscosity
Ans:
water has a higher surface tension
Explanation :
Dispersion is used to separate a beam of white light into its constituent spectrum of colours. This phenomenon leads to rainbow.
[8] A small gap is left at the joints of rails in a railway track to –
A.
avoid the tracks being distorted due to seasonal temperature variation
B.
avoid the heating of tracks to high temperature
C.
control the speed of train
D.
keep the rails equidistant
Ans:
avoid the tracks being distorted due to seasonal temperature variation
Explanation :
A small gap is left at the joints of rails in a railway track to provide space for the expansion of rai l pieces when the temperature rises during summer.
[9] Which of the following criterion is used for any metal to be used as a cooking material?
A.
More specific heat
B.
More thermal conductivity
C.
Less thermal conductivity
D.
Less electrical conductivity
Ans:
Less thermal conductivity
Explanation :
A metal to be used as a cooking material should have less thermal conductivity.
[10] Super conductors are substances that –
A.
offer minimum resistance to flow of electric current
B.
conduct electricity at low temperature
C.
conduct electricity at high temperature
D.
offer high resistance to the flow of electric current
Ans:
offer minimum resistance to flow of electric current
Explanation :
A superconductor is a material that can conduct electricity or transport electrons from one atom to another with no resistance. No heat, sound or any other form of energy is released from the material when it reaches the temperature at which it becomes superconductive.
[11] Cloudy nights are wanner compared nights, because clouds mainly –
A.
Absorb heat from the atmosphere send it towards earth
B.
Prevent cold waves from the sky descending on earth
C.
Reflect back the heat given by earth
D.
Produce heat and radiate it toward earth
Ans:
Reflect back the heat given by earth
Explanation :
It is because the night side of Earth will radiate infra-red radiation (heat) back into space. When there is cloud cover, the clouds act like a blanket and trap the heat close to the ground just like a blanket traps heat close to our body.
[12] Kepler's law of planetary motion states that the square of the time period is proportional to the –
A.
semi-major axis
B.
square of the semi-major axis
C.
cube of the semi-major axis
D.
fourth power of the serni-major axis
Ans:
cube of the semi-major axis
Explanation :
Kepler's law of planetary motion states that the square of the time period is proportional to the cube of the semi-major axis.
[13] Spring tides occur when:
A.
the moon, the sun and the earth are in the same line
B.
the sun is closest to earth
C.
the moon is farthest from earth
D.
the earth is at right angles with the sun and the moon
Ans:
the moon, the sun and the earth are in the same line
Explanation :
The combined tide raising forces of the Moon and the Sun are at their greatest effect when the Sun and the Moon are in line with the Earth.
[14] When a ship enters the sea from a river –
A.
It rises a little
B.
It sinks a little
C.
It remains at the same level
D.
It rises or sinks depending on the material it is made of
Ans:
It rises a little
Explanation :
On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, or 599 mM). Seawater is denser than hot fresh water and pure water (density 1.0 g/ml) because the dissolved salts add mass without contributing significantly to the volume.
[15] Why are we able to hear short wave broadcasts better than long wave broadcasts?
A.
Short waves are more energetic than long waves
B.
Short waves are unaffected by atmospheric disturbances
C.
Short wave broadcasts are made by nearby radio stations
D.
By convention, short waves are meant for long distances, whereas long waves are reserved for short distances
Ans:
Short waves are more energetic than long waves
Explanation :
Shortwave radio is used for broadcasting of voice and music, and long-distance communication to ships and aircraft, or to remote areas out of reach of wired communication or other radio services and that's why it is more energetic than long waves.
[16] In severe winter, in cold countries water pipes burst because –
A.
Water expands on freezing
B.
Contraction of water pipes
C.
High atmospheric pressure
D.
Combined effect of all the above three
Ans:
Water expands on freezing
Explanation :
Most liquids have a quite simple behavior when they are cooled (at a fixed pressure): they shrink. The liquid contract as it is cooled; because the molecules are moving slower they are less able to overcome the attractive intermolecular forces drawing them closer to each other. Then the freezing temperature is reached, and the substance solidifies, which causes it to contract some more because crystalline solids are usually tightly packed.
[17] A television channel is characterized by –
A.
frequency of transmitted signal
B.
velocity of transmitted signal
C.
physical dimension of television screen
D.
size of picture tube
Ans:
frequency of transmitted signal
Explanation :
A television channel is a physical or virtual channel over which a television station or television network is distributed. Channel numbers represent actual frequencies used to broadcast the television signal. For example, in North America, "channel 2" refers to the broadcast or cable band of 54 to 60 MHz, with carrier frequencies of 55.25 MHz for NTSC analog video (VSB) and 59.75 MHz for analog audio (FM), or 55.31 MHz for digital ATSC (8VSB).
[18] Which one of the following not a feature of Indifference Curve?
A.
They do not intersect each other
B.
They slope downwards to the right
C.
They are parallel to each other
D.
They are concave to each other
Ans:
They are concave to each other
Explanation :
Indifference curves are usually convex to the origin. In other words, the indifference curve is relatively flatter in its right-hand portion and relatively steeper in its left-hand portion. The degree of convexity of an indifference curve depends on the rate of fall in the marginal rate of substitution.
[19] Heat energy of an object is -
A.
The average energy of the molecules of the object
B.
The total energy of the molecules of the object
C.
The average velocity of the molecules of the object
D.
The average P.E. of the molecules of the object
Ans:
The total energy of the molecules of the object
Explanation :
The transfer or flow due to the difference in temperature between the two objects is called heat. Heat energy of an object is the total energy of the molecules of the object.
[20] If a body moves with a constant speed in a circle –
A.
no work is done on it
B.
no force acts on it
C.
no acceleration is produced in it
D.
its velocity remains constant
Ans:
its velocity remains constant
Explanation :
A body moving with a constant speed in a circle is an example of uniform circular motion. The velocity vector is constant in magnitude but changing in direction. Since velocity is a vector quantity that has both magnitude and direction, a change in either the magnitude or the direction constitutes a change in the velocity which leads to change in acceleration.
[21] A white and smooth surface is –
A.
good absorber and good reflector of heat
B.
bad absorber and good reflector of heat
C.
good absorber and bad reflector of heat
D.
bad absorber and bad reflector of heat
Ans:
bad absorber and good reflector of heat
Explanation :
Shiny surfaces are poor absorbers of heat radiation and the best reflectors of heat radiation. Black surfaces are the best emitters and best absorber of heat radiation.
[22] It is easier for a man to swim in sea water, than in river water because –
A.
the density of sea water is lesser than the density of river water
B.
the density of sea water is more than the density of river water
C.
the sea is deeper than the river
D.
the sea is wider than the river
Ans:
the density of sea water is more than the density of river water
Explanation :
the density of sea water is more than the density of river water
[23] In the pressure cooker, cooking is faster because the increase in vapour pressure -
A.
increase the specific heat
B.
decreases the specific heat
C.
decreases the boiling point
D.
increases the boiling point
Ans:
increases the boiling point
Explanation :
0
[24] Kinetic energy depends on –
A.
the velocity or speed of the moving body.
B.
the mass of the moving body
C.
the pressure of the moving body
D.
both mass and velocity of the moving body
Ans:
both mass and velocity of the moving body
Explanation :
Kinetic energy is the energy associated with the movement of objects. The amount of kinetic energy that an object has depends upon two variables: the mass (m) of the object and the speed (v) of the object.
[25] The apparent weight of a man in a lift is less the real weight when –
A.
the lift is going up with an acceleration
B.
the lift is going down with uniform speed
C.
the lift is going up with uniform speed
D.
the lift is going down with an acceleration
Ans:
the lift is going down with an acceleration
Explanation :
If the lift accelerates downwards with acceleration a, then the apparent weight of the man standing in the lift will be less than the true weight of the man by an amount ma. On the contrary, if the lift accelerates upwards with acceleration, then the apparent weight of the man will be greater than his true weight.
Explanation :
Dispersion is used to separate a beam of white light into its constituent spectrum of colours. This phenomenon leads to rainbow.
[8] A small gap is left at the joints of rails in a railway track to –
A.
avoid the tracks being distorted due to seasonal temperature variation
B.
avoid the heating of tracks to high temperature
C.
control the speed of train
D.
keep the rails equidistant
Ans:
avoid the tracks being distorted due to seasonal temperature variation
Explanation :
A small gap is left at the joints of rails in a railway track to provide space for the expansion of rai l pieces when the temperature rises during summer.
[9] Which of the following criterion is used for any metal to be used as a cooking material?
A.
More specific heat
B.
More thermal conductivity
C.
Less thermal conductivity
D.
Less electrical conductivity
Ans:
Less thermal conductivity
Explanation :
A metal to be used as a cooking material should have less thermal conductivity.
[10] Super conductors are substances that –
A.
offer minimum resistance to flow of electric current
B.
conduct electricity at low temperature
C.
conduct electricity at high temperature
D.
offer high resistance to the flow of electric current
Ans:
offer minimum resistance to flow of electric current
Explanation :
A superconductor is a material that can conduct electricity or transport electrons from one atom to another with no resistance. No heat, sound or any other form of energy is released from the material when it reaches the temperature at which it becomes superconductive.
[11] Cloudy nights are wanner compared nights, because clouds mainly –
A.
Absorb heat from the atmosphere send it towards earth
B.
Prevent cold waves from the sky descending on earth
C.
Reflect back the heat given by earth
D.
Produce heat and radiate it toward earth
Ans:
Reflect back the heat given by earth
Explanation :
It is because the night side of Earth will radiate infra-red radiation (heat) back into space. When there is cloud cover, the clouds act like a blanket and trap the heat close to the ground just like a blanket traps heat close to our body.
[12] Kepler's law of planetary motion states that the square of the time period is proportional to the –
A.
semi-major axis
B.
square of the semi-major axis
C.
cube of the semi-major axis
D.
fourth power of the serni-major axis
Ans:
cube of the semi-major axis
Explanation :
Kepler's law of planetary motion states that the square of the time period is proportional to the cube of the semi-major axis.
[13] Spring tides occur when:
A.
the moon, the sun and the earth are in the same line
B.
the sun is closest to earth
C.
the moon is farthest from earth
D.
the earth is at right angles with the sun and the moon
Ans:
the moon, the sun and the earth are in the same line
Explanation :
The combined tide raising forces of the Moon and the Sun are at their greatest effect when the Sun and the Moon are in line with the Earth.
[14] When a ship enters the sea from a river –
A.
It rises a little
B.
It sinks a little
C.
It remains at the same level
D.
It rises or sinks depending on the material it is made of
Ans:
It rises a little
Explanation :
On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, or 599 mM). Seawater is denser than hot fresh water and pure water (density 1.0 g/ml) because the dissolved salts add mass without contributing significantly to the volume.
[15] Why are we able to hear short wave broadcasts better than long wave broadcasts?
A.
Short waves are more energetic than long waves
B.
Short waves are unaffected by atmospheric disturbances
C.
Short wave broadcasts are made by nearby radio stations
D.
By convention, short waves are meant for long distances, whereas long waves are reserved for short distances
Ans:
Short waves are more energetic than long waves
Explanation :
Shortwave radio is used for broadcasting of voice and music, and long-distance communication to ships and aircraft, or to remote areas out of reach of wired communication or other radio services and that's why it is more energetic than long waves.
[16] In severe winter, in cold countries water pipes burst because –
A.
Water expands on freezing
B.
Contraction of water pipes
C.
High atmospheric pressure
D.
Combined effect of all the above three
Ans:
Water expands on freezing
Explanation :
Most liquids have a quite simple behavior when they are cooled (at a fixed pressure): they shrink. The liquid contract as it is cooled; because the molecules are moving slower they are less able to overcome the attractive intermolecular forces drawing them closer to each other. Then the freezing temperature is reached, and the substance solidifies, which causes it to contract some more because crystalline solids are usually tightly packed.
[17] A television channel is characterized by –
A.
frequency of transmitted signal
B.
velocity of transmitted signal
C.
physical dimension of television screen
D.
size of picture tube
Ans:
frequency of transmitted signal
Explanation :
A television channel is a physical or virtual channel over which a television station or television network is distributed. Channel numbers represent actual frequencies used to broadcast the television signal. For example, in North America, "channel 2" refers to the broadcast or cable band of 54 to 60 MHz, with carrier frequencies of 55.25 MHz for NTSC analog video (VSB) and 59.75 MHz for analog audio (FM), or 55.31 MHz for digital ATSC (8VSB).
[18] Which one of the following not a feature of Indifference Curve?
A.
They do not intersect each other
B.
They slope downwards to the right
C.
They are parallel to each other
D.
They are concave to each other
Ans:
They are concave to each other
Explanation :
Indifference curves are usually convex to the origin. In other words, the indifference curve is relatively flatter in its right-hand portion and relatively steeper in its left-hand portion. The degree of convexity of an indifference curve depends on the rate of fall in the marginal rate of substitution.
[19] Heat energy of an object is -
A.
The average energy of the molecules of the object
B.
The total energy of the molecules of the object
C.
The average velocity of the molecules of the object
D.
The average P.E. of the molecules of the object
Ans:
The total energy of the molecules of the object
Explanation :
The transfer or flow due to the difference in temperature between the two objects is called heat. Heat energy of an object is the total energy of the molecules of the object.
[20] If a body moves with a constant speed in a circle –
A.
no work is done on it
B.
no force acts on it
C.
no acceleration is produced in it
D.
its velocity remains constant
Ans:
its velocity remains constant
Explanation :
A body moving with a constant speed in a circle is an example of uniform circular motion. The velocity vector is constant in magnitude but changing in direction. Since velocity is a vector quantity that has both magnitude and direction, a change in either the magnitude or the direction constitutes a change in the velocity which leads to change in acceleration.
[21] A white and smooth surface is –
A.
good absorber and good reflector of heat
B.
bad absorber and good reflector of heat
C.
good absorber and bad reflector of heat
D.
bad absorber and bad reflector of heat
Ans:
bad absorber and good reflector of heat
Explanation :
Shiny surfaces are poor absorbers of heat radiation and the best reflectors of heat radiation. Black surfaces are the best emitters and best absorber of heat radiation.
[22] It is easier for a man to swim in sea water, than in river water because –
A.
the density of sea water is lesser than the density of river water
B.
the density of sea water is more than the density of river water
C.
the sea is deeper than the river
D.
the sea is wider than the river
Ans:
the density of sea water is more than the density of river water
Explanation :
the density of sea water is more than the density of river water
[23] In the pressure cooker, cooking is faster because the increase in vapour pressure -
A.
increase the specific heat
B.
decreases the specific heat
C.
decreases the boiling point
D.
increases the boiling point
Ans:
increases the boiling point
Explanation :
0
[24] Kinetic energy depends on –
A.
the velocity or speed of the moving body.
B.
the mass of the moving body
C.
the pressure of the moving body
D.
both mass and velocity of the moving body
Ans:
both mass and velocity of the moving body
Explanation :
Kinetic energy is the energy associated with the movement of objects. The amount of kinetic energy that an object has depends upon two variables: the mass (m) of the object and the speed (v) of the object.
[25] The apparent weight of a man in a lift is less the real weight when –
A.
the lift is going up with an acceleration
B.
the lift is going down with uniform speed
C.
the lift is going up with uniform speed
D.
the lift is going down with an acceleration
Ans:
the lift is going down with an acceleration
Explanation :
If the lift accelerates downwards with acceleration a, then the apparent weight of the man standing in the lift will be less than the true weight of the man by an amount ma. On the contrary, if the lift accelerates upwards with acceleration, then the apparent weight of the man will be greater than his true weight.
Explanation :
A metal to be used as a cooking material should have less thermal conductivity.
[10] Super conductors are substances that –
A.
offer minimum resistance to flow of electric current
B.
conduct electricity at low temperature
C.
conduct electricity at high temperature
D.
offer high resistance to the flow of electric current
Ans:
offer minimum resistance to flow of electric current
Explanation :
A superconductor is a material that can conduct electricity or transport electrons from one atom to another with no resistance. No heat, sound or any other form of energy is released from the material when it reaches the temperature at which it becomes superconductive.
[11] Cloudy nights are wanner compared nights, because clouds mainly –
A.
Absorb heat from the atmosphere send it towards earth
B.
Prevent cold waves from the sky descending on earth
C.
Reflect back the heat given by earth
D.
Produce heat and radiate it toward earth
Ans:
Reflect back the heat given by earth
Explanation :
It is because the night side of Earth will radiate infra-red radiation (heat) back into space. When there is cloud cover, the clouds act like a blanket and trap the heat close to the ground just like a blanket traps heat close to our body.
[12] Kepler's law of planetary motion states that the square of the time period is proportional to the –
A.
semi-major axis
B.
square of the semi-major axis
C.
cube of the semi-major axis
D.
fourth power of the serni-major axis
Ans:
cube of the semi-major axis
Explanation :
Kepler's law of planetary motion states that the square of the time period is proportional to the cube of the semi-major axis.
[13] Spring tides occur when:
A.
the moon, the sun and the earth are in the same line
B.
the sun is closest to earth
C.
the moon is farthest from earth
D.
the earth is at right angles with the sun and the moon
Ans:
the moon, the sun and the earth are in the same line
Explanation :
The combined tide raising forces of the Moon and the Sun are at their greatest effect when the Sun and the Moon are in line with the Earth.
[14] When a ship enters the sea from a river –
A.
It rises a little
B.
It sinks a little
C.
It remains at the same level
D.
It rises or sinks depending on the material it is made of
Ans:
It rises a little
Explanation :
On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, or 599 mM). Seawater is denser than hot fresh water and pure water (density 1.0 g/ml) because the dissolved salts add mass without contributing significantly to the volume.
[15] Why are we able to hear short wave broadcasts better than long wave broadcasts?
A.
Short waves are more energetic than long waves
B.
Short waves are unaffected by atmospheric disturbances
C.
Short wave broadcasts are made by nearby radio stations
D.
By convention, short waves are meant for long distances, whereas long waves are reserved for short distances
Ans:
Short waves are more energetic than long waves
Explanation :
Shortwave radio is used for broadcasting of voice and music, and long-distance communication to ships and aircraft, or to remote areas out of reach of wired communication or other radio services and that's why it is more energetic than long waves.
[16] In severe winter, in cold countries water pipes burst because –
A.
Water expands on freezing
B.
Contraction of water pipes
C.
High atmospheric pressure
D.
Combined effect of all the above three
Ans:
Water expands on freezing
Explanation :
Most liquids have a quite simple behavior when they are cooled (at a fixed pressure): they shrink. The liquid contract as it is cooled; because the molecules are moving slower they are less able to overcome the attractive intermolecular forces drawing them closer to each other. Then the freezing temperature is reached, and the substance solidifies, which causes it to contract some more because crystalline solids are usually tightly packed.
[17] A television channel is characterized by –
A.
frequency of transmitted signal
B.
velocity of transmitted signal
C.
physical dimension of television screen
D.
size of picture tube
Ans:
frequency of transmitted signal
Explanation :
A television channel is a physical or virtual channel over which a television station or television network is distributed. Channel numbers represent actual frequencies used to broadcast the television signal. For example, in North America, "channel 2" refers to the broadcast or cable band of 54 to 60 MHz, with carrier frequencies of 55.25 MHz for NTSC analog video (VSB) and 59.75 MHz for analog audio (FM), or 55.31 MHz for digital ATSC (8VSB).
[18] Which one of the following not a feature of Indifference Curve?
A.
They do not intersect each other
B.
They slope downwards to the right
C.
They are parallel to each other
D.
They are concave to each other
Ans:
They are concave to each other
Explanation :
Indifference curves are usually convex to the origin. In other words, the indifference curve is relatively flatter in its right-hand portion and relatively steeper in its left-hand portion. The degree of convexity of an indifference curve depends on the rate of fall in the marginal rate of substitution.
[19] Heat energy of an object is -
A.
The average energy of the molecules of the object
B.
The total energy of the molecules of the object
C.
The average velocity of the molecules of the object
D.
The average P.E. of the molecules of the object
Ans:
The total energy of the molecules of the object
Explanation :
The transfer or flow due to the difference in temperature between the two objects is called heat. Heat energy of an object is the total energy of the molecules of the object.
[20] If a body moves with a constant speed in a circle –
A.
no work is done on it
B.
no force acts on it
C.
no acceleration is produced in it
D.
its velocity remains constant
Ans:
its velocity remains constant
Explanation :
A body moving with a constant speed in a circle is an example of uniform circular motion. The velocity vector is constant in magnitude but changing in direction. Since velocity is a vector quantity that has both magnitude and direction, a change in either the magnitude or the direction constitutes a change in the velocity which leads to change in acceleration.
[21] A white and smooth surface is –
A.
good absorber and good reflector of heat
B.
bad absorber and good reflector of heat
C.
good absorber and bad reflector of heat
D.
bad absorber and bad reflector of heat
Ans:
bad absorber and good reflector of heat
Explanation :
Shiny surfaces are poor absorbers of heat radiation and the best reflectors of heat radiation. Black surfaces are the best emitters and best absorber of heat radiation.
[22] It is easier for a man to swim in sea water, than in river water because –
A.
the density of sea water is lesser than the density of river water
B.
the density of sea water is more than the density of river water
C.
the sea is deeper than the river
D.
the sea is wider than the river
Ans:
the density of sea water is more than the density of river water
Explanation :
the density of sea water is more than the density of river water
[23] In the pressure cooker, cooking is faster because the increase in vapour pressure -
A.
increase the specific heat
B.
decreases the specific heat
C.
decreases the boiling point
D.
increases the boiling point
Ans:
increases the boiling point
Explanation :
0
[24] Kinetic energy depends on –
A.
the velocity or speed of the moving body.
B.
the mass of the moving body
C.
the pressure of the moving body
D.
both mass and velocity of the moving body
Ans:
both mass and velocity of the moving body
Explanation :
Kinetic energy is the energy associated with the movement of objects. The amount of kinetic energy that an object has depends upon two variables: the mass (m) of the object and the speed (v) of the object.
[25] The apparent weight of a man in a lift is less the real weight when –
A.
the lift is going up with an acceleration
B.
the lift is going down with uniform speed
C.
the lift is going up with uniform speed
D.
the lift is going down with an acceleration
Ans:
the lift is going down with an acceleration
Explanation :
If the lift accelerates downwards with acceleration a, then the apparent weight of the man standing in the lift will be less than the true weight of the man by an amount ma. On the contrary, if the lift accelerates upwards with acceleration, then the apparent weight of the man will be greater than his true weight.
Explanation :
It is because the night side of Earth will radiate infra-red radiation (heat) back into space. When there is cloud cover, the clouds act like a blanket and trap the heat close to the ground just like a blanket traps heat close to our body.
[12] Kepler's law of planetary motion states that the square of the time period is proportional to the –
A.
semi-major axis
B.
square of the semi-major axis
C.
cube of the semi-major axis
D.
fourth power of the serni-major axis
Ans:
cube of the semi-major axis
Explanation :
Kepler's law of planetary motion states that the square of the time period is proportional to the cube of the semi-major axis.
[13] Spring tides occur when:
A.
the moon, the sun and the earth are in the same line
B.
the sun is closest to earth
C.
the moon is farthest from earth
D.
the earth is at right angles with the sun and the moon
Ans:
the moon, the sun and the earth are in the same line
Explanation :
The combined tide raising forces of the Moon and the Sun are at their greatest effect when the Sun and the Moon are in line with the Earth.
[14] When a ship enters the sea from a river –
A.
It rises a little
B.
It sinks a little
C.
It remains at the same level
D.
It rises or sinks depending on the material it is made of
Ans:
It rises a little
Explanation :
On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, or 599 mM). Seawater is denser than hot fresh water and pure water (density 1.0 g/ml) because the dissolved salts add mass without contributing significantly to the volume.
[15] Why are we able to hear short wave broadcasts better than long wave broadcasts?
A.
Short waves are more energetic than long waves
B.
Short waves are unaffected by atmospheric disturbances
C.
Short wave broadcasts are made by nearby radio stations
D.
By convention, short waves are meant for long distances, whereas long waves are reserved for short distances
Ans:
Short waves are more energetic than long waves
Explanation :
Shortwave radio is used for broadcasting of voice and music, and long-distance communication to ships and aircraft, or to remote areas out of reach of wired communication or other radio services and that's why it is more energetic than long waves.
[16] In severe winter, in cold countries water pipes burst because –
A.
Water expands on freezing
B.
Contraction of water pipes
C.
High atmospheric pressure
D.
Combined effect of all the above three
Ans:
Water expands on freezing
Explanation :
Most liquids have a quite simple behavior when they are cooled (at a fixed pressure): they shrink. The liquid contract as it is cooled; because the molecules are moving slower they are less able to overcome the attractive intermolecular forces drawing them closer to each other. Then the freezing temperature is reached, and the substance solidifies, which causes it to contract some more because crystalline solids are usually tightly packed.
[17] A television channel is characterized by –
A.
frequency of transmitted signal
B.
velocity of transmitted signal
C.
physical dimension of television screen
D.
size of picture tube
Ans:
frequency of transmitted signal
Explanation :
A television channel is a physical or virtual channel over which a television station or television network is distributed. Channel numbers represent actual frequencies used to broadcast the television signal. For example, in North America, "channel 2" refers to the broadcast or cable band of 54 to 60 MHz, with carrier frequencies of 55.25 MHz for NTSC analog video (VSB) and 59.75 MHz for analog audio (FM), or 55.31 MHz for digital ATSC (8VSB).
[18] Which one of the following not a feature of Indifference Curve?
A.
They do not intersect each other
B.
They slope downwards to the right
C.
They are parallel to each other
D.
They are concave to each other
Ans:
They are concave to each other
Explanation :
Indifference curves are usually convex to the origin. In other words, the indifference curve is relatively flatter in its right-hand portion and relatively steeper in its left-hand portion. The degree of convexity of an indifference curve depends on the rate of fall in the marginal rate of substitution.
[19] Heat energy of an object is -
A.
The average energy of the molecules of the object
B.
The total energy of the molecules of the object
C.
The average velocity of the molecules of the object
D.
The average P.E. of the molecules of the object
Ans:
The total energy of the molecules of the object
Explanation :
The transfer or flow due to the difference in temperature between the two objects is called heat. Heat energy of an object is the total energy of the molecules of the object.
[20] If a body moves with a constant speed in a circle –
A.
no work is done on it
B.
no force acts on it
C.
no acceleration is produced in it
D.
its velocity remains constant
Ans:
its velocity remains constant
Explanation :
A body moving with a constant speed in a circle is an example of uniform circular motion. The velocity vector is constant in magnitude but changing in direction. Since velocity is a vector quantity that has both magnitude and direction, a change in either the magnitude or the direction constitutes a change in the velocity which leads to change in acceleration.
[21] A white and smooth surface is –
A.
good absorber and good reflector of heat
B.
bad absorber and good reflector of heat
C.
good absorber and bad reflector of heat
D.
bad absorber and bad reflector of heat
Ans:
bad absorber and good reflector of heat
Explanation :
Shiny surfaces are poor absorbers of heat radiation and the best reflectors of heat radiation. Black surfaces are the best emitters and best absorber of heat radiation.
[22] It is easier for a man to swim in sea water, than in river water because –
A.
the density of sea water is lesser than the density of river water
B.
the density of sea water is more than the density of river water
C.
the sea is deeper than the river
D.
the sea is wider than the river
Ans:
the density of sea water is more than the density of river water
Explanation :
the density of sea water is more than the density of river water
[23] In the pressure cooker, cooking is faster because the increase in vapour pressure -
A.
increase the specific heat
B.
decreases the specific heat
C.
decreases the boiling point
D.
increases the boiling point
Ans:
increases the boiling point
Explanation :
0
[24] Kinetic energy depends on –
A.
the velocity or speed of the moving body.
B.
the mass of the moving body
C.
the pressure of the moving body
D.
both mass and velocity of the moving body
Ans:
both mass and velocity of the moving body
Explanation :
Kinetic energy is the energy associated with the movement of objects. The amount of kinetic energy that an object has depends upon two variables: the mass (m) of the object and the speed (v) of the object.
[25] The apparent weight of a man in a lift is less the real weight when –
A.
the lift is going up with an acceleration
B.
the lift is going down with uniform speed
C.
the lift is going up with uniform speed
D.
the lift is going down with an acceleration
Ans:
the lift is going down with an acceleration
Explanation :
If the lift accelerates downwards with acceleration a, then the apparent weight of the man standing in the lift will be less than the true weight of the man by an amount ma. On the contrary, if the lift accelerates upwards with acceleration, then the apparent weight of the man will be greater than his true weight.
Explanation :
The combined tide raising forces of the Moon and the Sun are at their greatest effect when the Sun and the Moon are in line with the Earth.
[14] When a ship enters the sea from a river –
A.
It rises a little
B.
It sinks a little
C.
It remains at the same level
D.
It rises or sinks depending on the material it is made of
Ans:
It rises a little
Explanation :
On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, or 599 mM). Seawater is denser than hot fresh water and pure water (density 1.0 g/ml) because the dissolved salts add mass without contributing significantly to the volume.
[15] Why are we able to hear short wave broadcasts better than long wave broadcasts?
A.
Short waves are more energetic than long waves
B.
Short waves are unaffected by atmospheric disturbances
C.
Short wave broadcasts are made by nearby radio stations
D.
By convention, short waves are meant for long distances, whereas long waves are reserved for short distances
Ans:
Short waves are more energetic than long waves
Explanation :
Shortwave radio is used for broadcasting of voice and music, and long-distance communication to ships and aircraft, or to remote areas out of reach of wired communication or other radio services and that's why it is more energetic than long waves.
[16] In severe winter, in cold countries water pipes burst because –
A.
Water expands on freezing
B.
Contraction of water pipes
C.
High atmospheric pressure
D.
Combined effect of all the above three
Ans:
Water expands on freezing
Explanation :
Most liquids have a quite simple behavior when they are cooled (at a fixed pressure): they shrink. The liquid contract as it is cooled; because the molecules are moving slower they are less able to overcome the attractive intermolecular forces drawing them closer to each other. Then the freezing temperature is reached, and the substance solidifies, which causes it to contract some more because crystalline solids are usually tightly packed.
[17] A television channel is characterized by –
A.
frequency of transmitted signal
B.
velocity of transmitted signal
C.
physical dimension of television screen
D.
size of picture tube
Ans:
frequency of transmitted signal
Explanation :
A television channel is a physical or virtual channel over which a television station or television network is distributed. Channel numbers represent actual frequencies used to broadcast the television signal. For example, in North America, "channel 2" refers to the broadcast or cable band of 54 to 60 MHz, with carrier frequencies of 55.25 MHz for NTSC analog video (VSB) and 59.75 MHz for analog audio (FM), or 55.31 MHz for digital ATSC (8VSB).
[18] Which one of the following not a feature of Indifference Curve?
A.
They do not intersect each other
B.
They slope downwards to the right
C.
They are parallel to each other
D.
They are concave to each other
Ans:
They are concave to each other
Explanation :
Indifference curves are usually convex to the origin. In other words, the indifference curve is relatively flatter in its right-hand portion and relatively steeper in its left-hand portion. The degree of convexity of an indifference curve depends on the rate of fall in the marginal rate of substitution.
[19] Heat energy of an object is -
A.
The average energy of the molecules of the object
B.
The total energy of the molecules of the object
C.
The average velocity of the molecules of the object
D.
The average P.E. of the molecules of the object
Ans:
The total energy of the molecules of the object
Explanation :
The transfer or flow due to the difference in temperature between the two objects is called heat. Heat energy of an object is the total energy of the molecules of the object.
[20] If a body moves with a constant speed in a circle –
A.
no work is done on it
B.
no force acts on it
C.
no acceleration is produced in it
D.
its velocity remains constant
Ans:
its velocity remains constant
Explanation :
A body moving with a constant speed in a circle is an example of uniform circular motion. The velocity vector is constant in magnitude but changing in direction. Since velocity is a vector quantity that has both magnitude and direction, a change in either the magnitude or the direction constitutes a change in the velocity which leads to change in acceleration.
[21] A white and smooth surface is –
A.
good absorber and good reflector of heat
B.
bad absorber and good reflector of heat
C.
good absorber and bad reflector of heat
D.
bad absorber and bad reflector of heat
Ans:
bad absorber and good reflector of heat
Explanation :
Shiny surfaces are poor absorbers of heat radiation and the best reflectors of heat radiation. Black surfaces are the best emitters and best absorber of heat radiation.
[22] It is easier for a man to swim in sea water, than in river water because –
A.
the density of sea water is lesser than the density of river water
B.
the density of sea water is more than the density of river water
C.
the sea is deeper than the river
D.
the sea is wider than the river
Ans:
the density of sea water is more than the density of river water
Explanation :
the density of sea water is more than the density of river water
[23] In the pressure cooker, cooking is faster because the increase in vapour pressure -
A.
increase the specific heat
B.
decreases the specific heat
C.
decreases the boiling point
D.
increases the boiling point
Ans:
increases the boiling point
Explanation :
0
[24] Kinetic energy depends on –
A.
the velocity or speed of the moving body.
B.
the mass of the moving body
C.
the pressure of the moving body
D.
both mass and velocity of the moving body
Ans:
both mass and velocity of the moving body
Explanation :
Kinetic energy is the energy associated with the movement of objects. The amount of kinetic energy that an object has depends upon two variables: the mass (m) of the object and the speed (v) of the object.
[25] The apparent weight of a man in a lift is less the real weight when –
A.
the lift is going up with an acceleration
B.
the lift is going down with uniform speed
C.
the lift is going up with uniform speed
D.
the lift is going down with an acceleration
Ans:
the lift is going down with an acceleration
Explanation :
If the lift accelerates downwards with acceleration a, then the apparent weight of the man standing in the lift will be less than the true weight of the man by an amount ma. On the contrary, if the lift accelerates upwards with acceleration, then the apparent weight of the man will be greater than his true weight.
Explanation :
Shortwave radio is used for broadcasting of voice and music, and long-distance communication to ships and aircraft, or to remote areas out of reach of wired communication or other radio services and that's why it is more energetic than long waves.
[16] In severe winter, in cold countries water pipes burst because –
A.
Water expands on freezing
B.
Contraction of water pipes
C.
High atmospheric pressure
D.
Combined effect of all the above three
Ans:
Water expands on freezing
Explanation :
Most liquids have a quite simple behavior when they are cooled (at a fixed pressure): they shrink. The liquid contract as it is cooled; because the molecules are moving slower they are less able to overcome the attractive intermolecular forces drawing them closer to each other. Then the freezing temperature is reached, and the substance solidifies, which causes it to contract some more because crystalline solids are usually tightly packed.
[17] A television channel is characterized by –
A.
frequency of transmitted signal
B.
velocity of transmitted signal
C.
physical dimension of television screen
D.
size of picture tube
Ans:
frequency of transmitted signal
Explanation :
A television channel is a physical or virtual channel over which a television station or television network is distributed. Channel numbers represent actual frequencies used to broadcast the television signal. For example, in North America, "channel 2" refers to the broadcast or cable band of 54 to 60 MHz, with carrier frequencies of 55.25 MHz for NTSC analog video (VSB) and 59.75 MHz for analog audio (FM), or 55.31 MHz for digital ATSC (8VSB).
[18] Which one of the following not a feature of Indifference Curve?
A.
They do not intersect each other
B.
They slope downwards to the right
C.
They are parallel to each other
D.
They are concave to each other
Ans:
They are concave to each other
Explanation :
Indifference curves are usually convex to the origin. In other words, the indifference curve is relatively flatter in its right-hand portion and relatively steeper in its left-hand portion. The degree of convexity of an indifference curve depends on the rate of fall in the marginal rate of substitution.
[19] Heat energy of an object is -
A.
The average energy of the molecules of the object
B.
The total energy of the molecules of the object
C.
The average velocity of the molecules of the object
D.
The average P.E. of the molecules of the object
Ans:
The total energy of the molecules of the object
Explanation :
The transfer or flow due to the difference in temperature between the two objects is called heat. Heat energy of an object is the total energy of the molecules of the object.
[20] If a body moves with a constant speed in a circle –
A.
no work is done on it
B.
no force acts on it
C.
no acceleration is produced in it
D.
its velocity remains constant
Ans:
its velocity remains constant
Explanation :
A body moving with a constant speed in a circle is an example of uniform circular motion. The velocity vector is constant in magnitude but changing in direction. Since velocity is a vector quantity that has both magnitude and direction, a change in either the magnitude or the direction constitutes a change in the velocity which leads to change in acceleration.
[21] A white and smooth surface is –
A.
good absorber and good reflector of heat
B.
bad absorber and good reflector of heat
C.
good absorber and bad reflector of heat
D.
bad absorber and bad reflector of heat
Ans:
bad absorber and good reflector of heat
Explanation :
Shiny surfaces are poor absorbers of heat radiation and the best reflectors of heat radiation. Black surfaces are the best emitters and best absorber of heat radiation.
[22] It is easier for a man to swim in sea water, than in river water because –
A.
the density of sea water is lesser than the density of river water
B.
the density of sea water is more than the density of river water
C.
the sea is deeper than the river
D.
the sea is wider than the river
Ans:
the density of sea water is more than the density of river water
Explanation :
the density of sea water is more than the density of river water
[23] In the pressure cooker, cooking is faster because the increase in vapour pressure -
A.
increase the specific heat
B.
decreases the specific heat
C.
decreases the boiling point
D.
increases the boiling point
Ans:
increases the boiling point
Explanation :
0
[24] Kinetic energy depends on –
A.
the velocity or speed of the moving body.
B.
the mass of the moving body
C.
the pressure of the moving body
D.
both mass and velocity of the moving body
Ans:
both mass and velocity of the moving body
Explanation :
Kinetic energy is the energy associated with the movement of objects. The amount of kinetic energy that an object has depends upon two variables: the mass (m) of the object and the speed (v) of the object.
[25] The apparent weight of a man in a lift is less the real weight when –
A.
the lift is going up with an acceleration
B.
the lift is going down with uniform speed
C.
the lift is going up with uniform speed
D.
the lift is going down with an acceleration
Ans:
the lift is going down with an acceleration
Explanation :
If the lift accelerates downwards with acceleration a, then the apparent weight of the man standing in the lift will be less than the true weight of the man by an amount ma. On the contrary, if the lift accelerates upwards with acceleration, then the apparent weight of the man will be greater than his true weight.
Explanation :
A television channel is a physical or virtual channel over which a television station or television network is distributed. Channel numbers represent actual frequencies used to broadcast the television signal. For example, in North America, "channel 2" refers to the broadcast or cable band of 54 to 60 MHz, with carrier frequencies of 55.25 MHz for NTSC analog video (VSB) and 59.75 MHz for analog audio (FM), or 55.31 MHz for digital ATSC (8VSB).
[18] Which one of the following not a feature of Indifference Curve?
A.
They do not intersect each other
B.
They slope downwards to the right
C.
They are parallel to each other
D.
They are concave to each other
Ans:
They are concave to each other
Explanation :
Indifference curves are usually convex to the origin. In other words, the indifference curve is relatively flatter in its right-hand portion and relatively steeper in its left-hand portion. The degree of convexity of an indifference curve depends on the rate of fall in the marginal rate of substitution.
[19] Heat energy of an object is -
A.
The average energy of the molecules of the object
B.
The total energy of the molecules of the object
C.
The average velocity of the molecules of the object
D.
The average P.E. of the molecules of the object
Ans:
The total energy of the molecules of the object
Explanation :
The transfer or flow due to the difference in temperature between the two objects is called heat. Heat energy of an object is the total energy of the molecules of the object.
[20] If a body moves with a constant speed in a circle –
A.
no work is done on it
B.
no force acts on it
C.
no acceleration is produced in it
D.
its velocity remains constant
Ans:
its velocity remains constant
Explanation :
A body moving with a constant speed in a circle is an example of uniform circular motion. The velocity vector is constant in magnitude but changing in direction. Since velocity is a vector quantity that has both magnitude and direction, a change in either the magnitude or the direction constitutes a change in the velocity which leads to change in acceleration.
[21] A white and smooth surface is –
A.
good absorber and good reflector of heat
B.
bad absorber and good reflector of heat
C.
good absorber and bad reflector of heat
D.
bad absorber and bad reflector of heat
Ans:
bad absorber and good reflector of heat
Explanation :
Shiny surfaces are poor absorbers of heat radiation and the best reflectors of heat radiation. Black surfaces are the best emitters and best absorber of heat radiation.
[22] It is easier for a man to swim in sea water, than in river water because –
A.
the density of sea water is lesser than the density of river water
B.
the density of sea water is more than the density of river water
C.
the sea is deeper than the river
D.
the sea is wider than the river
Ans:
the density of sea water is more than the density of river water
Explanation :
the density of sea water is more than the density of river water
[23] In the pressure cooker, cooking is faster because the increase in vapour pressure -
A.
increase the specific heat
B.
decreases the specific heat
C.
decreases the boiling point
D.
increases the boiling point
Ans:
increases the boiling point
Explanation :
0
[24] Kinetic energy depends on –
A.
the velocity or speed of the moving body.
B.
the mass of the moving body
C.
the pressure of the moving body
D.
both mass and velocity of the moving body
Ans:
both mass and velocity of the moving body
Explanation :
Kinetic energy is the energy associated with the movement of objects. The amount of kinetic energy that an object has depends upon two variables: the mass (m) of the object and the speed (v) of the object.
[25] The apparent weight of a man in a lift is less the real weight when –
A.
the lift is going up with an acceleration
B.
the lift is going down with uniform speed
C.
the lift is going up with uniform speed
D.
the lift is going down with an acceleration
Ans:
the lift is going down with an acceleration
Explanation :
If the lift accelerates downwards with acceleration a, then the apparent weight of the man standing in the lift will be less than the true weight of the man by an amount ma. On the contrary, if the lift accelerates upwards with acceleration, then the apparent weight of the man will be greater than his true weight.
Explanation :
The transfer or flow due to the difference in temperature between the two objects is called heat. Heat energy of an object is the total energy of the molecules of the object.
[20] If a body moves with a constant speed in a circle –
A.
no work is done on it
B.
no force acts on it
C.
no acceleration is produced in it
D.
its velocity remains constant
Ans:
its velocity remains constant
Explanation :
A body moving with a constant speed in a circle is an example of uniform circular motion. The velocity vector is constant in magnitude but changing in direction. Since velocity is a vector quantity that has both magnitude and direction, a change in either the magnitude or the direction constitutes a change in the velocity which leads to change in acceleration.
[21] A white and smooth surface is –
A.
good absorber and good reflector of heat
B.
bad absorber and good reflector of heat
C.
good absorber and bad reflector of heat
D.
bad absorber and bad reflector of heat
Ans:
bad absorber and good reflector of heat
Explanation :
Shiny surfaces are poor absorbers of heat radiation and the best reflectors of heat radiation. Black surfaces are the best emitters and best absorber of heat radiation.
[22] It is easier for a man to swim in sea water, than in river water because –
A.
the density of sea water is lesser than the density of river water
B.
the density of sea water is more than the density of river water
C.
the sea is deeper than the river
D.
the sea is wider than the river
Ans:
the density of sea water is more than the density of river water
Explanation :
the density of sea water is more than the density of river water
[23] In the pressure cooker, cooking is faster because the increase in vapour pressure -
A.
increase the specific heat
B.
decreases the specific heat
C.
decreases the boiling point
D.
increases the boiling point
Ans:
increases the boiling point
Explanation :
0
[24] Kinetic energy depends on –
A.
the velocity or speed of the moving body.
B.
the mass of the moving body
C.
the pressure of the moving body
D.
both mass and velocity of the moving body
Ans:
both mass and velocity of the moving body
Explanation :
Kinetic energy is the energy associated with the movement of objects. The amount of kinetic energy that an object has depends upon two variables: the mass (m) of the object and the speed (v) of the object.
[25] The apparent weight of a man in a lift is less the real weight when –
A.
the lift is going up with an acceleration
B.
the lift is going down with uniform speed
C.
the lift is going up with uniform speed
D.
the lift is going down with an acceleration
Ans:
the lift is going down with an acceleration
Explanation :
If the lift accelerates downwards with acceleration a, then the apparent weight of the man standing in the lift will be less than the true weight of the man by an amount ma. On the contrary, if the lift accelerates upwards with acceleration, then the apparent weight of the man will be greater than his true weight.
Explanation :
Shiny surfaces are poor absorbers of heat radiation and the best reflectors of heat radiation. Black surfaces are the best emitters and best absorber of heat radiation.
[22] It is easier for a man to swim in sea water, than in river water because –
A.
the density of sea water is lesser than the density of river water
B.
the density of sea water is more than the density of river water
C.
the sea is deeper than the river
D.
the sea is wider than the river
Ans:
the density of sea water is more than the density of river water
Explanation :
the density of sea water is more than the density of river water
[23] In the pressure cooker, cooking is faster because the increase in vapour pressure -
A.
increase the specific heat
B.
decreases the specific heat
C.
decreases the boiling point
D.
increases the boiling point
Ans:
increases the boiling point
Explanation :
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[24] Kinetic energy depends on –
A.
the velocity or speed of the moving body.
B.
the mass of the moving body
C.
the pressure of the moving body
D.
both mass and velocity of the moving body
Ans:
both mass and velocity of the moving body
Explanation :
Kinetic energy is the energy associated with the movement of objects. The amount of kinetic energy that an object has depends upon two variables: the mass (m) of the object and the speed (v) of the object.
[25] The apparent weight of a man in a lift is less the real weight when –
A.
the lift is going up with an acceleration
B.
the lift is going down with uniform speed
C.
the lift is going up with uniform speed
D.
the lift is going down with an acceleration
Ans:
the lift is going down with an acceleration
Explanation :
If the lift accelerates downwards with acceleration a, then the apparent weight of the man standing in the lift will be less than the true weight of the man by an amount ma. On the contrary, if the lift accelerates upwards with acceleration, then the apparent weight of the man will be greater than his true weight.
Explanation :
0
[24] Kinetic energy depends on –
A.
the velocity or speed of the moving body.
B.
the mass of the moving body
C.
the pressure of the moving body
D.
both mass and velocity of the moving body
Ans:
both mass and velocity of the moving body
Explanation :
Kinetic energy is the energy associated with the movement of objects. The amount of kinetic energy that an object has depends upon two variables: the mass (m) of the object and the speed (v) of the object.
[25] The apparent weight of a man in a lift is less the real weight when –
A.
the lift is going up with an acceleration
B.
the lift is going down with uniform speed
C.
the lift is going up with uniform speed
D.
the lift is going down with an acceleration
Ans:
the lift is going down with an acceleration
Explanation :
If the lift accelerates downwards with acceleration a, then the apparent weight of the man standing in the lift will be less than the true weight of the man by an amount ma. On the contrary, if the lift accelerates upwards with acceleration, then the apparent weight of the man will be greater than his true weight.
Explanation :
If the lift accelerates downwards with acceleration a, then the apparent weight of the man standing in the lift will be less than the true weight of the man by an amount ma. On the contrary, if the lift accelerates upwards with acceleration, then the apparent weight of the man will be greater than his true weight.