[1] Which layer of the earth’s atmosphere reflects back the radio waves to the earth’s surface?
A.
Ionosphere
B.
Stratosphere
C.
Mesosphere
D.
Exosphere
Ans:
Ionosphere
Explanation :
Long distance propagation of radio waves depends on an invisible layer of charged particles, which envelops the Earth. This layer of charged particles known as the ionosphere has been in existence for millions of years. For those, who pioneered the long distance radio communication during the early part of the twentieth century, the ionosphere came as a boon.
[2] What is the process of melting also called?
A.
Fusion
B.
Galvanisation
C.
Crystallisatiorn
D.
Evaporation
Ans:
Fusion
Explanation :
Melting, or fusion is a physical process that results in the phase transition of a substance from a solid to a liquid.
[3] A man inside an artificial satellite feels weightlessness because the force of attraction due to earth is –
A.
zero at that place
B.
is balanced by the force of attraction due to moon
C.
equal to the centripetal force
D.
non-effective due to particular design of the satellite
Ans:
zero at that place
Explanation :
Earth attracts all bodies towards its centre. The acceleration produced in the body due to attraction force of earth on it is called the acceleration due to gravity. A astronaut in a satellite experiences weightlessness because two forces act on him: gravitational pull and centrifugal force which cancel out each other with the resultant force acting on him being zero.
[4] 'Shock-absorbers are usually made of steel as it –
A.
is not brittle
B.
has lower elasticity
C.
has higher elasticity
D.
has no ductile property
Ans:
has higher elasticity
Explanation :
A shock absorber is a mechanical device designed to smooth out or damp shock impulse, and dissipate kinetic energy. Steel is an alloy made by combining iron and other elements, the most common of these being carbon.
[5] What is the maximum value of deforming force upto which a material shows elastic property and above which the material loses it?
A.
Elasticity
B.
Strain
C.
Elastic Limit
D.
Stress
Ans:
Elastic Limit
Explanation :
The Maximum Extent to which a solid may be stretched without permanent alteration of size or shape.
[6] With the increase of pressure, the boiling point of any substance -
A.
Increases
B.
Decreases
C.
Remains Same
D.
Becomes zero
Ans:
Increases
Explanation :
The temperature stays the same until all the liquid has vaporized. As the temperature of a liquid rises, the pressure of escaping vapor also rises, and at the boiling point the pressure of the escaping vapor is equal to that exerted on the liquid by the surrounding air, causing bubbles to form.
[7] Among the following materials sound travels fastest in –
A.
Steel
B.
Air
C.
Vacuum
D.
Water
Ans:
Steel
Explanation :
The speed of sound is the distance travelled during a unit of time by a sound wave propagating through an elastic medium. In dry air at 20 °C (68 °F), the speed of sound is 343.2 metres per second (1,126 ft/s). the speed of sound varies from substance to substance. Sound travels faster in liquids and non-porous solids than it does in air.
[8] Velocity of the sound is minimum in -
A.
Steel
B.
Vacuum
C.
Water
D.
Air
Ans:
Vacuum
Explanation :
The speed of sound in a vacuum is zero meters per second, as sound cannot travel in a vacuum. Sound is a wave, which means it spreads through the vibration of particles in a medium, such as water or air.
[9] Safety fuse wire used in domestic electrical appliances is made of metal of low –
A.
Resistance
B.
Melting point
C.
Specific gravity
D.
Conductance
Ans:
Melting point
Explanation :
The fuse wire is based on the Joules law of heating which says that when the electric current is allowed to pass through a conductor, the conductor heats up and is proportional to the square of current. The main object of using fuse wire in electric circuit is to provide protection against short circuit or overload current. For this purpose the material used as fuse wire should have high resistance and low melting point.
[10] The following particles move with same kinetic energy. Which of them has maximum momentum?
A.
Electron
B.
Proton
C.
Deutron
D.
Alpha Particle
Ans:
Alpha Particle
Explanation :
The formula for kinetic energy in terms of momentum for fundamental particles is basically just a quantized version of the classical formula, KE=(P2)/2m, where KE is kinetic energy, p is momentum and m is the particle’s mass.
[11] A bottle of sodalime is grasped by the neck and swung briskly in a vertical circle, Near which portion of the bottle do the bubbles collect?
A.
Near the bottom
B.
In the middle of the bottom
C.
Near the neck
D.
Bubbles remain distributed uniformly
Ans:
Near the neck
Explanation :
When the bottle of soda water is grasped by the neck and swung briskly in a vertical circle, the bubbles collect at the top of the bottle which is its neck. What flows in a carbonated drink is carbon dioxide gas. A carbonated beverage forms form bubbles when the dissolved carbon dioxide is depressurized to form emulsions at the top.
[12] Lambert's law is related to –
A.
Reflection
B.
Refraction
C.
Interference
D.
Illumination
Ans:
Illumination
Explanation :
In optics, Lambert's cosine law says that the radiant intensity or luminous intensity observed from an ideal diffusely reflecting surface or ideal diffuse radiator is directly proportional to the cosine of the angle between the observer's line of sight and the surface normal. The law is also known as the cosine emission law or Lambert's emission law.
[13] When a detergent is added to pure water, its surface tension –
A.
increases
B.
decreases
C.
remains constant
D.
becomes infinite
Ans:
decreases
Explanation :
When Soaps and detergents are added to water, they weaken the strength of the skin on the water's surface due to surface tension by interfering with hydrogen bonding between water molecules. It happens because the polar end of the soap or detergent is also attracted to the water, thereby decreasing the surface tension.
[14] Small bubbles are perfectly spherical because of –
A.
Gravity
B.
Pressure
C.
Viscosity
D.
Surface tension
Ans:
Surface tension
Explanation :
Surface tension is responsible for the shape of liquid droplets. Although easily deformed, droplets of water tend to be pulled into a spherical shape by the cohesive forces of the surface layer. In the absence of other forces, including gravity, drops of virtually an liquids would be perfectly spherical. The spherical shape minimizes the necessary "wall tension" of the surface layer according to Laplace's law.
[15] The final image in a simple microscope is –
A.
real, diminished and inverted
B.
real, magnified and erect
C.
virtual, magnified and erect
D.
virtual, diminished and erect
Ans:
virtual, magnified and erect
Explanation :
A basic microscope is made up of two converging lenses. The first lens creates a real image which serves as the object for the second lens, and the image created by the second lens is the one a viewer sees. The final image is magnified, virtual and is inverted compared to the original object.
[16] A radioactive substance emits?
A.
alpha particle
B.
beta particle
C.
gamma particle
D.
all of the three
Ans:
all of the three
Explanation :
Radioactive substances are continually producing three kinds of dangerous radiation: alpha particles, beta particles and gamma rays. These types of radiation are invisible to the naked eye, and so you won't see a green glow.
[17] A single fixed pulley is used to draw water from a well because –
A.
efficiency is 100%
B.
velocity ratio is low
C.
mechanical advantage is high
D.
force is applied in a convenient direction
Ans:
force is applied in a convenient direction
Explanation :
A single fixed pulley is used to lift a load upwards by applying efforts downwards. The load and effort move equal distance but in opposite directions. This is convenient as to apply effort in downward direction. They are used on flag-poles and to draw water from a well.
[18] Hyperrnetropia or longsight can be corrected by using :
A.
Bifocal lenses
B.
Cylindrical lenses
C.
Concave lenses
D.
Convex lenses
Ans:
Convex lenses
Explanation :
It can be corrected with convex lenses in eyeglasses or contact lenses. Convex lenses have a positive dioptric value, which causes the light to focus closer than its normal range.
[19] Stars appear twinkling because of of light.
A.
Reflection
B.
Scattering
C.
Emission
D.
Absorption
Ans:
Scattering
Explanation :
The stars' light must travel through the Earth's multi-layered atmosphere, and as it does so it is refracted (bent) multiple times and in random directions. The phenomenon of random refraction appears to make the star wink as though it is in motion. It is this action that our eyes translate as twinkling.
[20] In mirrors the back surface is coated with a thin layer of :
A.
Mercury
B.
Silver
C.
Red oxide
D.
Silver nitrate
Ans:
Silver
Explanation :
In a spherical mirror, one of the two curved surfaces is coated with a thin layer of silver followed by a coating of red lead oxide paint. Thus, one side of the spherical minor is opaque and the other side is a highly polished reflecting surface.
[21] A bomb at rest explodes into a large number of tiny fragments. The total momentum of all the fragments –
A.
is zero
B.
depends on the total mass of all the fragments
C.
depends on the speeds of various fragments
D.
is infinity
Ans:
is zero
Explanation :
In an explosion, an internal impulse acts in order to propel the parts of a system (often a single object) into a variety of directions. After the explosion, the individual parts of the system (that is often a collection of fragments from the original object) have momentum.
[22] Sound energy passing per second through a unit area held perpendicular is called -
A.
Intensity
B.
Frequency
C.
Amplitude
D.
Quality
Ans:
Intensity
Explanation :
Sound energy passes through a unit area held perpendicular to the direction of propagation of sound waves is called intensity of sound.
[23] Which one of the following is used to remove Astigmatism for a human eye?
A.
Concave lens
B.
Convex lens
C.
Cylindrical lens
D.
Prismatic lens
Ans:
Cylindrical lens
Explanation :
A cylindrical lens is a lens which focuses light into a line instead of a point, as a spherical lens would.
[24] Speed of sound in air is unaffected by change in :
A.
Pressure
B.
Humidity
C.
Temperature
D.
Volume
Ans:
Pressure
Explanation :
The speed of sound in air depends on the density of air and the density of air depends on the temperature. The speed of sound is unaffected by pressure. If the atmospheric pressure changes, the speed of sound in air remains constant.
[25] The audio signals of TV are :
A.
Amplitude modulated
B.
Frequency modulated
C.
Unmodulated
D.
Velocity modulated
Ans:
Frequency modulated
Explanation :
In telecommunications and signal processing, frequency modulation (FM) conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant. In analogue television, the sound portion of a broadcast is invariably modulated separately from the video.
Explanation :
Long distance propagation of radio waves depends on an invisible layer of charged particles, which envelops the Earth. This layer of charged particles known as the ionosphere has been in existence for millions of years. For those, who pioneered the long distance radio communication during the early part of the twentieth century, the ionosphere came as a boon.
[2] What is the process of melting also called?
A.
Fusion
B.
Galvanisation
C.
Crystallisatiorn
D.
Evaporation
Ans:
Fusion
Explanation :
Melting, or fusion is a physical process that results in the phase transition of a substance from a solid to a liquid.
[3] A man inside an artificial satellite feels weightlessness because the force of attraction due to earth is –
A.
zero at that place
B.
is balanced by the force of attraction due to moon
C.
equal to the centripetal force
D.
non-effective due to particular design of the satellite
Ans:
zero at that place
Explanation :
Earth attracts all bodies towards its centre. The acceleration produced in the body due to attraction force of earth on it is called the acceleration due to gravity. A astronaut in a satellite experiences weightlessness because two forces act on him: gravitational pull and centrifugal force which cancel out each other with the resultant force acting on him being zero.
[4] 'Shock-absorbers are usually made of steel as it –
A.
is not brittle
B.
has lower elasticity
C.
has higher elasticity
D.
has no ductile property
Ans:
has higher elasticity
Explanation :
A shock absorber is a mechanical device designed to smooth out or damp shock impulse, and dissipate kinetic energy. Steel is an alloy made by combining iron and other elements, the most common of these being carbon.
[5] What is the maximum value of deforming force upto which a material shows elastic property and above which the material loses it?
A.
Elasticity
B.
Strain
C.
Elastic Limit
D.
Stress
Ans:
Elastic Limit
Explanation :
The Maximum Extent to which a solid may be stretched without permanent alteration of size or shape.
[6] With the increase of pressure, the boiling point of any substance -
A.
Increases
B.
Decreases
C.
Remains Same
D.
Becomes zero
Ans:
Increases
Explanation :
The temperature stays the same until all the liquid has vaporized. As the temperature of a liquid rises, the pressure of escaping vapor also rises, and at the boiling point the pressure of the escaping vapor is equal to that exerted on the liquid by the surrounding air, causing bubbles to form.
[7] Among the following materials sound travels fastest in –
A.
Steel
B.
Air
C.
Vacuum
D.
Water
Ans:
Steel
Explanation :
The speed of sound is the distance travelled during a unit of time by a sound wave propagating through an elastic medium. In dry air at 20 °C (68 °F), the speed of sound is 343.2 metres per second (1,126 ft/s). the speed of sound varies from substance to substance. Sound travels faster in liquids and non-porous solids than it does in air.
[8] Velocity of the sound is minimum in -
A.
Steel
B.
Vacuum
C.
Water
D.
Air
Ans:
Vacuum
Explanation :
The speed of sound in a vacuum is zero meters per second, as sound cannot travel in a vacuum. Sound is a wave, which means it spreads through the vibration of particles in a medium, such as water or air.
[9] Safety fuse wire used in domestic electrical appliances is made of metal of low –
A.
Resistance
B.
Melting point
C.
Specific gravity
D.
Conductance
Ans:
Melting point
Explanation :
The fuse wire is based on the Joules law of heating which says that when the electric current is allowed to pass through a conductor, the conductor heats up and is proportional to the square of current. The main object of using fuse wire in electric circuit is to provide protection against short circuit or overload current. For this purpose the material used as fuse wire should have high resistance and low melting point.
[10] The following particles move with same kinetic energy. Which of them has maximum momentum?
A.
Electron
B.
Proton
C.
Deutron
D.
Alpha Particle
Ans:
Alpha Particle
Explanation :
The formula for kinetic energy in terms of momentum for fundamental particles is basically just a quantized version of the classical formula, KE=(P2)/2m, where KE is kinetic energy, p is momentum and m is the particle’s mass.
[11] A bottle of sodalime is grasped by the neck and swung briskly in a vertical circle, Near which portion of the bottle do the bubbles collect?
A.
Near the bottom
B.
In the middle of the bottom
C.
Near the neck
D.
Bubbles remain distributed uniformly
Ans:
Near the neck
Explanation :
When the bottle of soda water is grasped by the neck and swung briskly in a vertical circle, the bubbles collect at the top of the bottle which is its neck. What flows in a carbonated drink is carbon dioxide gas. A carbonated beverage forms form bubbles when the dissolved carbon dioxide is depressurized to form emulsions at the top.
[12] Lambert's law is related to –
A.
Reflection
B.
Refraction
C.
Interference
D.
Illumination
Ans:
Illumination
Explanation :
In optics, Lambert's cosine law says that the radiant intensity or luminous intensity observed from an ideal diffusely reflecting surface or ideal diffuse radiator is directly proportional to the cosine of the angle between the observer's line of sight and the surface normal. The law is also known as the cosine emission law or Lambert's emission law.
[13] When a detergent is added to pure water, its surface tension –
A.
increases
B.
decreases
C.
remains constant
D.
becomes infinite
Ans:
decreases
Explanation :
When Soaps and detergents are added to water, they weaken the strength of the skin on the water's surface due to surface tension by interfering with hydrogen bonding between water molecules. It happens because the polar end of the soap or detergent is also attracted to the water, thereby decreasing the surface tension.
[14] Small bubbles are perfectly spherical because of –
A.
Gravity
B.
Pressure
C.
Viscosity
D.
Surface tension
Ans:
Surface tension
Explanation :
Surface tension is responsible for the shape of liquid droplets. Although easily deformed, droplets of water tend to be pulled into a spherical shape by the cohesive forces of the surface layer. In the absence of other forces, including gravity, drops of virtually an liquids would be perfectly spherical. The spherical shape minimizes the necessary "wall tension" of the surface layer according to Laplace's law.
[15] The final image in a simple microscope is –
A.
real, diminished and inverted
B.
real, magnified and erect
C.
virtual, magnified and erect
D.
virtual, diminished and erect
Ans:
virtual, magnified and erect
Explanation :
A basic microscope is made up of two converging lenses. The first lens creates a real image which serves as the object for the second lens, and the image created by the second lens is the one a viewer sees. The final image is magnified, virtual and is inverted compared to the original object.
[16] A radioactive substance emits?
A.
alpha particle
B.
beta particle
C.
gamma particle
D.
all of the three
Ans:
all of the three
Explanation :
Radioactive substances are continually producing three kinds of dangerous radiation: alpha particles, beta particles and gamma rays. These types of radiation are invisible to the naked eye, and so you won't see a green glow.
[17] A single fixed pulley is used to draw water from a well because –
A.
efficiency is 100%
B.
velocity ratio is low
C.
mechanical advantage is high
D.
force is applied in a convenient direction
Ans:
force is applied in a convenient direction
Explanation :
A single fixed pulley is used to lift a load upwards by applying efforts downwards. The load and effort move equal distance but in opposite directions. This is convenient as to apply effort in downward direction. They are used on flag-poles and to draw water from a well.
[18] Hyperrnetropia or longsight can be corrected by using :
A.
Bifocal lenses
B.
Cylindrical lenses
C.
Concave lenses
D.
Convex lenses
Ans:
Convex lenses
Explanation :
It can be corrected with convex lenses in eyeglasses or contact lenses. Convex lenses have a positive dioptric value, which causes the light to focus closer than its normal range.
[19] Stars appear twinkling because of of light.
A.
Reflection
B.
Scattering
C.
Emission
D.
Absorption
Ans:
Scattering
Explanation :
The stars' light must travel through the Earth's multi-layered atmosphere, and as it does so it is refracted (bent) multiple times and in random directions. The phenomenon of random refraction appears to make the star wink as though it is in motion. It is this action that our eyes translate as twinkling.
[20] In mirrors the back surface is coated with a thin layer of :
A.
Mercury
B.
Silver
C.
Red oxide
D.
Silver nitrate
Ans:
Silver
Explanation :
In a spherical mirror, one of the two curved surfaces is coated with a thin layer of silver followed by a coating of red lead oxide paint. Thus, one side of the spherical minor is opaque and the other side is a highly polished reflecting surface.
[21] A bomb at rest explodes into a large number of tiny fragments. The total momentum of all the fragments –
A.
is zero
B.
depends on the total mass of all the fragments
C.
depends on the speeds of various fragments
D.
is infinity
Ans:
is zero
Explanation :
In an explosion, an internal impulse acts in order to propel the parts of a system (often a single object) into a variety of directions. After the explosion, the individual parts of the system (that is often a collection of fragments from the original object) have momentum.
[22] Sound energy passing per second through a unit area held perpendicular is called -
A.
Intensity
B.
Frequency
C.
Amplitude
D.
Quality
Ans:
Intensity
Explanation :
Sound energy passes through a unit area held perpendicular to the direction of propagation of sound waves is called intensity of sound.
[23] Which one of the following is used to remove Astigmatism for a human eye?
A.
Concave lens
B.
Convex lens
C.
Cylindrical lens
D.
Prismatic lens
Ans:
Cylindrical lens
Explanation :
A cylindrical lens is a lens which focuses light into a line instead of a point, as a spherical lens would.
[24] Speed of sound in air is unaffected by change in :
A.
Pressure
B.
Humidity
C.
Temperature
D.
Volume
Ans:
Pressure
Explanation :
The speed of sound in air depends on the density of air and the density of air depends on the temperature. The speed of sound is unaffected by pressure. If the atmospheric pressure changes, the speed of sound in air remains constant.
[25] The audio signals of TV are :
A.
Amplitude modulated
B.
Frequency modulated
C.
Unmodulated
D.
Velocity modulated
Ans:
Frequency modulated
Explanation :
In telecommunications and signal processing, frequency modulation (FM) conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant. In analogue television, the sound portion of a broadcast is invariably modulated separately from the video.
Explanation :
Earth attracts all bodies towards its centre. The acceleration produced in the body due to attraction force of earth on it is called the acceleration due to gravity. A astronaut in a satellite experiences weightlessness because two forces act on him: gravitational pull and centrifugal force which cancel out each other with the resultant force acting on him being zero.
[4] 'Shock-absorbers are usually made of steel as it –
A.
is not brittle
B.
has lower elasticity
C.
has higher elasticity
D.
has no ductile property
Ans:
has higher elasticity
Explanation :
A shock absorber is a mechanical device designed to smooth out or damp shock impulse, and dissipate kinetic energy. Steel is an alloy made by combining iron and other elements, the most common of these being carbon.
[5] What is the maximum value of deforming force upto which a material shows elastic property and above which the material loses it?
A.
Elasticity
B.
Strain
C.
Elastic Limit
D.
Stress
Ans:
Elastic Limit
Explanation :
The Maximum Extent to which a solid may be stretched without permanent alteration of size or shape.
[6] With the increase of pressure, the boiling point of any substance -
A.
Increases
B.
Decreases
C.
Remains Same
D.
Becomes zero
Ans:
Increases
Explanation :
The temperature stays the same until all the liquid has vaporized. As the temperature of a liquid rises, the pressure of escaping vapor also rises, and at the boiling point the pressure of the escaping vapor is equal to that exerted on the liquid by the surrounding air, causing bubbles to form.
[7] Among the following materials sound travels fastest in –
A.
Steel
B.
Air
C.
Vacuum
D.
Water
Ans:
Steel
Explanation :
The speed of sound is the distance travelled during a unit of time by a sound wave propagating through an elastic medium. In dry air at 20 °C (68 °F), the speed of sound is 343.2 metres per second (1,126 ft/s). the speed of sound varies from substance to substance. Sound travels faster in liquids and non-porous solids than it does in air.
[8] Velocity of the sound is minimum in -
A.
Steel
B.
Vacuum
C.
Water
D.
Air
Ans:
Vacuum
Explanation :
The speed of sound in a vacuum is zero meters per second, as sound cannot travel in a vacuum. Sound is a wave, which means it spreads through the vibration of particles in a medium, such as water or air.
[9] Safety fuse wire used in domestic electrical appliances is made of metal of low –
A.
Resistance
B.
Melting point
C.
Specific gravity
D.
Conductance
Ans:
Melting point
Explanation :
The fuse wire is based on the Joules law of heating which says that when the electric current is allowed to pass through a conductor, the conductor heats up and is proportional to the square of current. The main object of using fuse wire in electric circuit is to provide protection against short circuit or overload current. For this purpose the material used as fuse wire should have high resistance and low melting point.
[10] The following particles move with same kinetic energy. Which of them has maximum momentum?
A.
Electron
B.
Proton
C.
Deutron
D.
Alpha Particle
Ans:
Alpha Particle
Explanation :
The formula for kinetic energy in terms of momentum for fundamental particles is basically just a quantized version of the classical formula, KE=(P2)/2m, where KE is kinetic energy, p is momentum and m is the particle’s mass.
[11] A bottle of sodalime is grasped by the neck and swung briskly in a vertical circle, Near which portion of the bottle do the bubbles collect?
A.
Near the bottom
B.
In the middle of the bottom
C.
Near the neck
D.
Bubbles remain distributed uniformly
Ans:
Near the neck
Explanation :
When the bottle of soda water is grasped by the neck and swung briskly in a vertical circle, the bubbles collect at the top of the bottle which is its neck. What flows in a carbonated drink is carbon dioxide gas. A carbonated beverage forms form bubbles when the dissolved carbon dioxide is depressurized to form emulsions at the top.
[12] Lambert's law is related to –
A.
Reflection
B.
Refraction
C.
Interference
D.
Illumination
Ans:
Illumination
Explanation :
In optics, Lambert's cosine law says that the radiant intensity or luminous intensity observed from an ideal diffusely reflecting surface or ideal diffuse radiator is directly proportional to the cosine of the angle between the observer's line of sight and the surface normal. The law is also known as the cosine emission law or Lambert's emission law.
[13] When a detergent is added to pure water, its surface tension –
A.
increases
B.
decreases
C.
remains constant
D.
becomes infinite
Ans:
decreases
Explanation :
When Soaps and detergents are added to water, they weaken the strength of the skin on the water's surface due to surface tension by interfering with hydrogen bonding between water molecules. It happens because the polar end of the soap or detergent is also attracted to the water, thereby decreasing the surface tension.
[14] Small bubbles are perfectly spherical because of –
A.
Gravity
B.
Pressure
C.
Viscosity
D.
Surface tension
Ans:
Surface tension
Explanation :
Surface tension is responsible for the shape of liquid droplets. Although easily deformed, droplets of water tend to be pulled into a spherical shape by the cohesive forces of the surface layer. In the absence of other forces, including gravity, drops of virtually an liquids would be perfectly spherical. The spherical shape minimizes the necessary "wall tension" of the surface layer according to Laplace's law.
[15] The final image in a simple microscope is –
A.
real, diminished and inverted
B.
real, magnified and erect
C.
virtual, magnified and erect
D.
virtual, diminished and erect
Ans:
virtual, magnified and erect
Explanation :
A basic microscope is made up of two converging lenses. The first lens creates a real image which serves as the object for the second lens, and the image created by the second lens is the one a viewer sees. The final image is magnified, virtual and is inverted compared to the original object.
[16] A radioactive substance emits?
A.
alpha particle
B.
beta particle
C.
gamma particle
D.
all of the three
Ans:
all of the three
Explanation :
Radioactive substances are continually producing three kinds of dangerous radiation: alpha particles, beta particles and gamma rays. These types of radiation are invisible to the naked eye, and so you won't see a green glow.
[17] A single fixed pulley is used to draw water from a well because –
A.
efficiency is 100%
B.
velocity ratio is low
C.
mechanical advantage is high
D.
force is applied in a convenient direction
Ans:
force is applied in a convenient direction
Explanation :
A single fixed pulley is used to lift a load upwards by applying efforts downwards. The load and effort move equal distance but in opposite directions. This is convenient as to apply effort in downward direction. They are used on flag-poles and to draw water from a well.
[18] Hyperrnetropia or longsight can be corrected by using :
A.
Bifocal lenses
B.
Cylindrical lenses
C.
Concave lenses
D.
Convex lenses
Ans:
Convex lenses
Explanation :
It can be corrected with convex lenses in eyeglasses or contact lenses. Convex lenses have a positive dioptric value, which causes the light to focus closer than its normal range.
[19] Stars appear twinkling because of of light.
A.
Reflection
B.
Scattering
C.
Emission
D.
Absorption
Ans:
Scattering
Explanation :
The stars' light must travel through the Earth's multi-layered atmosphere, and as it does so it is refracted (bent) multiple times and in random directions. The phenomenon of random refraction appears to make the star wink as though it is in motion. It is this action that our eyes translate as twinkling.
[20] In mirrors the back surface is coated with a thin layer of :
A.
Mercury
B.
Silver
C.
Red oxide
D.
Silver nitrate
Ans:
Silver
Explanation :
In a spherical mirror, one of the two curved surfaces is coated with a thin layer of silver followed by a coating of red lead oxide paint. Thus, one side of the spherical minor is opaque and the other side is a highly polished reflecting surface.
[21] A bomb at rest explodes into a large number of tiny fragments. The total momentum of all the fragments –
A.
is zero
B.
depends on the total mass of all the fragments
C.
depends on the speeds of various fragments
D.
is infinity
Ans:
is zero
Explanation :
In an explosion, an internal impulse acts in order to propel the parts of a system (often a single object) into a variety of directions. After the explosion, the individual parts of the system (that is often a collection of fragments from the original object) have momentum.
[22] Sound energy passing per second through a unit area held perpendicular is called -
A.
Intensity
B.
Frequency
C.
Amplitude
D.
Quality
Ans:
Intensity
Explanation :
Sound energy passes through a unit area held perpendicular to the direction of propagation of sound waves is called intensity of sound.
[23] Which one of the following is used to remove Astigmatism for a human eye?
A.
Concave lens
B.
Convex lens
C.
Cylindrical lens
D.
Prismatic lens
Ans:
Cylindrical lens
Explanation :
A cylindrical lens is a lens which focuses light into a line instead of a point, as a spherical lens would.
[24] Speed of sound in air is unaffected by change in :
A.
Pressure
B.
Humidity
C.
Temperature
D.
Volume
Ans:
Pressure
Explanation :
The speed of sound in air depends on the density of air and the density of air depends on the temperature. The speed of sound is unaffected by pressure. If the atmospheric pressure changes, the speed of sound in air remains constant.
[25] The audio signals of TV are :
A.
Amplitude modulated
B.
Frequency modulated
C.
Unmodulated
D.
Velocity modulated
Ans:
Frequency modulated
Explanation :
In telecommunications and signal processing, frequency modulation (FM) conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant. In analogue television, the sound portion of a broadcast is invariably modulated separately from the video.
Explanation :
The Maximum Extent to which a solid may be stretched without permanent alteration of size or shape.
[6] With the increase of pressure, the boiling point of any substance -
A.
Increases
B.
Decreases
C.
Remains Same
D.
Becomes zero
Ans:
Increases
Explanation :
The temperature stays the same until all the liquid has vaporized. As the temperature of a liquid rises, the pressure of escaping vapor also rises, and at the boiling point the pressure of the escaping vapor is equal to that exerted on the liquid by the surrounding air, causing bubbles to form.
[7] Among the following materials sound travels fastest in –
A.
Steel
B.
Air
C.
Vacuum
D.
Water
Ans:
Steel
Explanation :
The speed of sound is the distance travelled during a unit of time by a sound wave propagating through an elastic medium. In dry air at 20 °C (68 °F), the speed of sound is 343.2 metres per second (1,126 ft/s). the speed of sound varies from substance to substance. Sound travels faster in liquids and non-porous solids than it does in air.
[8] Velocity of the sound is minimum in -
A.
Steel
B.
Vacuum
C.
Water
D.
Air
Ans:
Vacuum
Explanation :
The speed of sound in a vacuum is zero meters per second, as sound cannot travel in a vacuum. Sound is a wave, which means it spreads through the vibration of particles in a medium, such as water or air.
[9] Safety fuse wire used in domestic electrical appliances is made of metal of low –
A.
Resistance
B.
Melting point
C.
Specific gravity
D.
Conductance
Ans:
Melting point
Explanation :
The fuse wire is based on the Joules law of heating which says that when the electric current is allowed to pass through a conductor, the conductor heats up and is proportional to the square of current. The main object of using fuse wire in electric circuit is to provide protection against short circuit or overload current. For this purpose the material used as fuse wire should have high resistance and low melting point.
[10] The following particles move with same kinetic energy. Which of them has maximum momentum?
A.
Electron
B.
Proton
C.
Deutron
D.
Alpha Particle
Ans:
Alpha Particle
Explanation :
The formula for kinetic energy in terms of momentum for fundamental particles is basically just a quantized version of the classical formula, KE=(P2)/2m, where KE is kinetic energy, p is momentum and m is the particle’s mass.
[11] A bottle of sodalime is grasped by the neck and swung briskly in a vertical circle, Near which portion of the bottle do the bubbles collect?
A.
Near the bottom
B.
In the middle of the bottom
C.
Near the neck
D.
Bubbles remain distributed uniformly
Ans:
Near the neck
Explanation :
When the bottle of soda water is grasped by the neck and swung briskly in a vertical circle, the bubbles collect at the top of the bottle which is its neck. What flows in a carbonated drink is carbon dioxide gas. A carbonated beverage forms form bubbles when the dissolved carbon dioxide is depressurized to form emulsions at the top.
[12] Lambert's law is related to –
A.
Reflection
B.
Refraction
C.
Interference
D.
Illumination
Ans:
Illumination
Explanation :
In optics, Lambert's cosine law says that the radiant intensity or luminous intensity observed from an ideal diffusely reflecting surface or ideal diffuse radiator is directly proportional to the cosine of the angle between the observer's line of sight and the surface normal. The law is also known as the cosine emission law or Lambert's emission law.
[13] When a detergent is added to pure water, its surface tension –
A.
increases
B.
decreases
C.
remains constant
D.
becomes infinite
Ans:
decreases
Explanation :
When Soaps and detergents are added to water, they weaken the strength of the skin on the water's surface due to surface tension by interfering with hydrogen bonding between water molecules. It happens because the polar end of the soap or detergent is also attracted to the water, thereby decreasing the surface tension.
[14] Small bubbles are perfectly spherical because of –
A.
Gravity
B.
Pressure
C.
Viscosity
D.
Surface tension
Ans:
Surface tension
Explanation :
Surface tension is responsible for the shape of liquid droplets. Although easily deformed, droplets of water tend to be pulled into a spherical shape by the cohesive forces of the surface layer. In the absence of other forces, including gravity, drops of virtually an liquids would be perfectly spherical. The spherical shape minimizes the necessary "wall tension" of the surface layer according to Laplace's law.
[15] The final image in a simple microscope is –
A.
real, diminished and inverted
B.
real, magnified and erect
C.
virtual, magnified and erect
D.
virtual, diminished and erect
Ans:
virtual, magnified and erect
Explanation :
A basic microscope is made up of two converging lenses. The first lens creates a real image which serves as the object for the second lens, and the image created by the second lens is the one a viewer sees. The final image is magnified, virtual and is inverted compared to the original object.
[16] A radioactive substance emits?
A.
alpha particle
B.
beta particle
C.
gamma particle
D.
all of the three
Ans:
all of the three
Explanation :
Radioactive substances are continually producing three kinds of dangerous radiation: alpha particles, beta particles and gamma rays. These types of radiation are invisible to the naked eye, and so you won't see a green glow.
[17] A single fixed pulley is used to draw water from a well because –
A.
efficiency is 100%
B.
velocity ratio is low
C.
mechanical advantage is high
D.
force is applied in a convenient direction
Ans:
force is applied in a convenient direction
Explanation :
A single fixed pulley is used to lift a load upwards by applying efforts downwards. The load and effort move equal distance but in opposite directions. This is convenient as to apply effort in downward direction. They are used on flag-poles and to draw water from a well.
[18] Hyperrnetropia or longsight can be corrected by using :
A.
Bifocal lenses
B.
Cylindrical lenses
C.
Concave lenses
D.
Convex lenses
Ans:
Convex lenses
Explanation :
It can be corrected with convex lenses in eyeglasses or contact lenses. Convex lenses have a positive dioptric value, which causes the light to focus closer than its normal range.
[19] Stars appear twinkling because of of light.
A.
Reflection
B.
Scattering
C.
Emission
D.
Absorption
Ans:
Scattering
Explanation :
The stars' light must travel through the Earth's multi-layered atmosphere, and as it does so it is refracted (bent) multiple times and in random directions. The phenomenon of random refraction appears to make the star wink as though it is in motion. It is this action that our eyes translate as twinkling.
[20] In mirrors the back surface is coated with a thin layer of :
A.
Mercury
B.
Silver
C.
Red oxide
D.
Silver nitrate
Ans:
Silver
Explanation :
In a spherical mirror, one of the two curved surfaces is coated with a thin layer of silver followed by a coating of red lead oxide paint. Thus, one side of the spherical minor is opaque and the other side is a highly polished reflecting surface.
[21] A bomb at rest explodes into a large number of tiny fragments. The total momentum of all the fragments –
A.
is zero
B.
depends on the total mass of all the fragments
C.
depends on the speeds of various fragments
D.
is infinity
Ans:
is zero
Explanation :
In an explosion, an internal impulse acts in order to propel the parts of a system (often a single object) into a variety of directions. After the explosion, the individual parts of the system (that is often a collection of fragments from the original object) have momentum.
[22] Sound energy passing per second through a unit area held perpendicular is called -
A.
Intensity
B.
Frequency
C.
Amplitude
D.
Quality
Ans:
Intensity
Explanation :
Sound energy passes through a unit area held perpendicular to the direction of propagation of sound waves is called intensity of sound.
[23] Which one of the following is used to remove Astigmatism for a human eye?
A.
Concave lens
B.
Convex lens
C.
Cylindrical lens
D.
Prismatic lens
Ans:
Cylindrical lens
Explanation :
A cylindrical lens is a lens which focuses light into a line instead of a point, as a spherical lens would.
[24] Speed of sound in air is unaffected by change in :
A.
Pressure
B.
Humidity
C.
Temperature
D.
Volume
Ans:
Pressure
Explanation :
The speed of sound in air depends on the density of air and the density of air depends on the temperature. The speed of sound is unaffected by pressure. If the atmospheric pressure changes, the speed of sound in air remains constant.
[25] The audio signals of TV are :
A.
Amplitude modulated
B.
Frequency modulated
C.
Unmodulated
D.
Velocity modulated
Ans:
Frequency modulated
Explanation :
In telecommunications and signal processing, frequency modulation (FM) conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant. In analogue television, the sound portion of a broadcast is invariably modulated separately from the video.
Explanation :
The speed of sound is the distance travelled during a unit of time by a sound wave propagating through an elastic medium. In dry air at 20 °C (68 °F), the speed of sound is 343.2 metres per second (1,126 ft/s). the speed of sound varies from substance to substance. Sound travels faster in liquids and non-porous solids than it does in air.
[8] Velocity of the sound is minimum in -
A.
Steel
B.
Vacuum
C.
Water
D.
Air
Ans:
Vacuum
Explanation :
The speed of sound in a vacuum is zero meters per second, as sound cannot travel in a vacuum. Sound is a wave, which means it spreads through the vibration of particles in a medium, such as water or air.
[9] Safety fuse wire used in domestic electrical appliances is made of metal of low –
A.
Resistance
B.
Melting point
C.
Specific gravity
D.
Conductance
Ans:
Melting point
Explanation :
The fuse wire is based on the Joules law of heating which says that when the electric current is allowed to pass through a conductor, the conductor heats up and is proportional to the square of current. The main object of using fuse wire in electric circuit is to provide protection against short circuit or overload current. For this purpose the material used as fuse wire should have high resistance and low melting point.
[10] The following particles move with same kinetic energy. Which of them has maximum momentum?
A.
Electron
B.
Proton
C.
Deutron
D.
Alpha Particle
Ans:
Alpha Particle
Explanation :
The formula for kinetic energy in terms of momentum for fundamental particles is basically just a quantized version of the classical formula, KE=(P2)/2m, where KE is kinetic energy, p is momentum and m is the particle’s mass.
[11] A bottle of sodalime is grasped by the neck and swung briskly in a vertical circle, Near which portion of the bottle do the bubbles collect?
A.
Near the bottom
B.
In the middle of the bottom
C.
Near the neck
D.
Bubbles remain distributed uniformly
Ans:
Near the neck
Explanation :
When the bottle of soda water is grasped by the neck and swung briskly in a vertical circle, the bubbles collect at the top of the bottle which is its neck. What flows in a carbonated drink is carbon dioxide gas. A carbonated beverage forms form bubbles when the dissolved carbon dioxide is depressurized to form emulsions at the top.
[12] Lambert's law is related to –
A.
Reflection
B.
Refraction
C.
Interference
D.
Illumination
Ans:
Illumination
Explanation :
In optics, Lambert's cosine law says that the radiant intensity or luminous intensity observed from an ideal diffusely reflecting surface or ideal diffuse radiator is directly proportional to the cosine of the angle between the observer's line of sight and the surface normal. The law is also known as the cosine emission law or Lambert's emission law.
[13] When a detergent is added to pure water, its surface tension –
A.
increases
B.
decreases
C.
remains constant
D.
becomes infinite
Ans:
decreases
Explanation :
When Soaps and detergents are added to water, they weaken the strength of the skin on the water's surface due to surface tension by interfering with hydrogen bonding between water molecules. It happens because the polar end of the soap or detergent is also attracted to the water, thereby decreasing the surface tension.
[14] Small bubbles are perfectly spherical because of –
A.
Gravity
B.
Pressure
C.
Viscosity
D.
Surface tension
Ans:
Surface tension
Explanation :
Surface tension is responsible for the shape of liquid droplets. Although easily deformed, droplets of water tend to be pulled into a spherical shape by the cohesive forces of the surface layer. In the absence of other forces, including gravity, drops of virtually an liquids would be perfectly spherical. The spherical shape minimizes the necessary "wall tension" of the surface layer according to Laplace's law.
[15] The final image in a simple microscope is –
A.
real, diminished and inverted
B.
real, magnified and erect
C.
virtual, magnified and erect
D.
virtual, diminished and erect
Ans:
virtual, magnified and erect
Explanation :
A basic microscope is made up of two converging lenses. The first lens creates a real image which serves as the object for the second lens, and the image created by the second lens is the one a viewer sees. The final image is magnified, virtual and is inverted compared to the original object.
[16] A radioactive substance emits?
A.
alpha particle
B.
beta particle
C.
gamma particle
D.
all of the three
Ans:
all of the three
Explanation :
Radioactive substances are continually producing three kinds of dangerous radiation: alpha particles, beta particles and gamma rays. These types of radiation are invisible to the naked eye, and so you won't see a green glow.
[17] A single fixed pulley is used to draw water from a well because –
A.
efficiency is 100%
B.
velocity ratio is low
C.
mechanical advantage is high
D.
force is applied in a convenient direction
Ans:
force is applied in a convenient direction
Explanation :
A single fixed pulley is used to lift a load upwards by applying efforts downwards. The load and effort move equal distance but in opposite directions. This is convenient as to apply effort in downward direction. They are used on flag-poles and to draw water from a well.
[18] Hyperrnetropia or longsight can be corrected by using :
A.
Bifocal lenses
B.
Cylindrical lenses
C.
Concave lenses
D.
Convex lenses
Ans:
Convex lenses
Explanation :
It can be corrected with convex lenses in eyeglasses or contact lenses. Convex lenses have a positive dioptric value, which causes the light to focus closer than its normal range.
[19] Stars appear twinkling because of of light.
A.
Reflection
B.
Scattering
C.
Emission
D.
Absorption
Ans:
Scattering
Explanation :
The stars' light must travel through the Earth's multi-layered atmosphere, and as it does so it is refracted (bent) multiple times and in random directions. The phenomenon of random refraction appears to make the star wink as though it is in motion. It is this action that our eyes translate as twinkling.
[20] In mirrors the back surface is coated with a thin layer of :
A.
Mercury
B.
Silver
C.
Red oxide
D.
Silver nitrate
Ans:
Silver
Explanation :
In a spherical mirror, one of the two curved surfaces is coated with a thin layer of silver followed by a coating of red lead oxide paint. Thus, one side of the spherical minor is opaque and the other side is a highly polished reflecting surface.
[21] A bomb at rest explodes into a large number of tiny fragments. The total momentum of all the fragments –
A.
is zero
B.
depends on the total mass of all the fragments
C.
depends on the speeds of various fragments
D.
is infinity
Ans:
is zero
Explanation :
In an explosion, an internal impulse acts in order to propel the parts of a system (often a single object) into a variety of directions. After the explosion, the individual parts of the system (that is often a collection of fragments from the original object) have momentum.
[22] Sound energy passing per second through a unit area held perpendicular is called -
A.
Intensity
B.
Frequency
C.
Amplitude
D.
Quality
Ans:
Intensity
Explanation :
Sound energy passes through a unit area held perpendicular to the direction of propagation of sound waves is called intensity of sound.
[23] Which one of the following is used to remove Astigmatism for a human eye?
A.
Concave lens
B.
Convex lens
C.
Cylindrical lens
D.
Prismatic lens
Ans:
Cylindrical lens
Explanation :
A cylindrical lens is a lens which focuses light into a line instead of a point, as a spherical lens would.
[24] Speed of sound in air is unaffected by change in :
A.
Pressure
B.
Humidity
C.
Temperature
D.
Volume
Ans:
Pressure
Explanation :
The speed of sound in air depends on the density of air and the density of air depends on the temperature. The speed of sound is unaffected by pressure. If the atmospheric pressure changes, the speed of sound in air remains constant.
[25] The audio signals of TV are :
A.
Amplitude modulated
B.
Frequency modulated
C.
Unmodulated
D.
Velocity modulated
Ans:
Frequency modulated
Explanation :
In telecommunications and signal processing, frequency modulation (FM) conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant. In analogue television, the sound portion of a broadcast is invariably modulated separately from the video.
Explanation :
The fuse wire is based on the Joules law of heating which says that when the electric current is allowed to pass through a conductor, the conductor heats up and is proportional to the square of current. The main object of using fuse wire in electric circuit is to provide protection against short circuit or overload current. For this purpose the material used as fuse wire should have high resistance and low melting point.
[10] The following particles move with same kinetic energy. Which of them has maximum momentum?
A.
Electron
B.
Proton
C.
Deutron
D.
Alpha Particle
Ans:
Alpha Particle
Explanation :
The formula for kinetic energy in terms of momentum for fundamental particles is basically just a quantized version of the classical formula, KE=(P2)/2m, where KE is kinetic energy, p is momentum and m is the particle’s mass.
[11] A bottle of sodalime is grasped by the neck and swung briskly in a vertical circle, Near which portion of the bottle do the bubbles collect?
A.
Near the bottom
B.
In the middle of the bottom
C.
Near the neck
D.
Bubbles remain distributed uniformly
Ans:
Near the neck
Explanation :
When the bottle of soda water is grasped by the neck and swung briskly in a vertical circle, the bubbles collect at the top of the bottle which is its neck. What flows in a carbonated drink is carbon dioxide gas. A carbonated beverage forms form bubbles when the dissolved carbon dioxide is depressurized to form emulsions at the top.
[12] Lambert's law is related to –
A.
Reflection
B.
Refraction
C.
Interference
D.
Illumination
Ans:
Illumination
Explanation :
In optics, Lambert's cosine law says that the radiant intensity or luminous intensity observed from an ideal diffusely reflecting surface or ideal diffuse radiator is directly proportional to the cosine of the angle between the observer's line of sight and the surface normal. The law is also known as the cosine emission law or Lambert's emission law.
[13] When a detergent is added to pure water, its surface tension –
A.
increases
B.
decreases
C.
remains constant
D.
becomes infinite
Ans:
decreases
Explanation :
When Soaps and detergents are added to water, they weaken the strength of the skin on the water's surface due to surface tension by interfering with hydrogen bonding between water molecules. It happens because the polar end of the soap or detergent is also attracted to the water, thereby decreasing the surface tension.
[14] Small bubbles are perfectly spherical because of –
A.
Gravity
B.
Pressure
C.
Viscosity
D.
Surface tension
Ans:
Surface tension
Explanation :
Surface tension is responsible for the shape of liquid droplets. Although easily deformed, droplets of water tend to be pulled into a spherical shape by the cohesive forces of the surface layer. In the absence of other forces, including gravity, drops of virtually an liquids would be perfectly spherical. The spherical shape minimizes the necessary "wall tension" of the surface layer according to Laplace's law.
[15] The final image in a simple microscope is –
A.
real, diminished and inverted
B.
real, magnified and erect
C.
virtual, magnified and erect
D.
virtual, diminished and erect
Ans:
virtual, magnified and erect
Explanation :
A basic microscope is made up of two converging lenses. The first lens creates a real image which serves as the object for the second lens, and the image created by the second lens is the one a viewer sees. The final image is magnified, virtual and is inverted compared to the original object.
[16] A radioactive substance emits?
A.
alpha particle
B.
beta particle
C.
gamma particle
D.
all of the three
Ans:
all of the three
Explanation :
Radioactive substances are continually producing three kinds of dangerous radiation: alpha particles, beta particles and gamma rays. These types of radiation are invisible to the naked eye, and so you won't see a green glow.
[17] A single fixed pulley is used to draw water from a well because –
A.
efficiency is 100%
B.
velocity ratio is low
C.
mechanical advantage is high
D.
force is applied in a convenient direction
Ans:
force is applied in a convenient direction
Explanation :
A single fixed pulley is used to lift a load upwards by applying efforts downwards. The load and effort move equal distance but in opposite directions. This is convenient as to apply effort in downward direction. They are used on flag-poles and to draw water from a well.
[18] Hyperrnetropia or longsight can be corrected by using :
A.
Bifocal lenses
B.
Cylindrical lenses
C.
Concave lenses
D.
Convex lenses
Ans:
Convex lenses
Explanation :
It can be corrected with convex lenses in eyeglasses or contact lenses. Convex lenses have a positive dioptric value, which causes the light to focus closer than its normal range.
[19] Stars appear twinkling because of of light.
A.
Reflection
B.
Scattering
C.
Emission
D.
Absorption
Ans:
Scattering
Explanation :
The stars' light must travel through the Earth's multi-layered atmosphere, and as it does so it is refracted (bent) multiple times and in random directions. The phenomenon of random refraction appears to make the star wink as though it is in motion. It is this action that our eyes translate as twinkling.
[20] In mirrors the back surface is coated with a thin layer of :
A.
Mercury
B.
Silver
C.
Red oxide
D.
Silver nitrate
Ans:
Silver
Explanation :
In a spherical mirror, one of the two curved surfaces is coated with a thin layer of silver followed by a coating of red lead oxide paint. Thus, one side of the spherical minor is opaque and the other side is a highly polished reflecting surface.
[21] A bomb at rest explodes into a large number of tiny fragments. The total momentum of all the fragments –
A.
is zero
B.
depends on the total mass of all the fragments
C.
depends on the speeds of various fragments
D.
is infinity
Ans:
is zero
Explanation :
In an explosion, an internal impulse acts in order to propel the parts of a system (often a single object) into a variety of directions. After the explosion, the individual parts of the system (that is often a collection of fragments from the original object) have momentum.
[22] Sound energy passing per second through a unit area held perpendicular is called -
A.
Intensity
B.
Frequency
C.
Amplitude
D.
Quality
Ans:
Intensity
Explanation :
Sound energy passes through a unit area held perpendicular to the direction of propagation of sound waves is called intensity of sound.
[23] Which one of the following is used to remove Astigmatism for a human eye?
A.
Concave lens
B.
Convex lens
C.
Cylindrical lens
D.
Prismatic lens
Ans:
Cylindrical lens
Explanation :
A cylindrical lens is a lens which focuses light into a line instead of a point, as a spherical lens would.
[24] Speed of sound in air is unaffected by change in :
A.
Pressure
B.
Humidity
C.
Temperature
D.
Volume
Ans:
Pressure
Explanation :
The speed of sound in air depends on the density of air and the density of air depends on the temperature. The speed of sound is unaffected by pressure. If the atmospheric pressure changes, the speed of sound in air remains constant.
[25] The audio signals of TV are :
A.
Amplitude modulated
B.
Frequency modulated
C.
Unmodulated
D.
Velocity modulated
Ans:
Frequency modulated
Explanation :
In telecommunications and signal processing, frequency modulation (FM) conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant. In analogue television, the sound portion of a broadcast is invariably modulated separately from the video.
Explanation :
When the bottle of soda water is grasped by the neck and swung briskly in a vertical circle, the bubbles collect at the top of the bottle which is its neck. What flows in a carbonated drink is carbon dioxide gas. A carbonated beverage forms form bubbles when the dissolved carbon dioxide is depressurized to form emulsions at the top.
[12] Lambert's law is related to –
A.
Reflection
B.
Refraction
C.
Interference
D.
Illumination
Ans:
Illumination
Explanation :
In optics, Lambert's cosine law says that the radiant intensity or luminous intensity observed from an ideal diffusely reflecting surface or ideal diffuse radiator is directly proportional to the cosine of the angle between the observer's line of sight and the surface normal. The law is also known as the cosine emission law or Lambert's emission law.
[13] When a detergent is added to pure water, its surface tension –
A.
increases
B.
decreases
C.
remains constant
D.
becomes infinite
Ans:
decreases
Explanation :
When Soaps and detergents are added to water, they weaken the strength of the skin on the water's surface due to surface tension by interfering with hydrogen bonding between water molecules. It happens because the polar end of the soap or detergent is also attracted to the water, thereby decreasing the surface tension.
[14] Small bubbles are perfectly spherical because of –
A.
Gravity
B.
Pressure
C.
Viscosity
D.
Surface tension
Ans:
Surface tension
Explanation :
Surface tension is responsible for the shape of liquid droplets. Although easily deformed, droplets of water tend to be pulled into a spherical shape by the cohesive forces of the surface layer. In the absence of other forces, including gravity, drops of virtually an liquids would be perfectly spherical. The spherical shape minimizes the necessary "wall tension" of the surface layer according to Laplace's law.
[15] The final image in a simple microscope is –
A.
real, diminished and inverted
B.
real, magnified and erect
C.
virtual, magnified and erect
D.
virtual, diminished and erect
Ans:
virtual, magnified and erect
Explanation :
A basic microscope is made up of two converging lenses. The first lens creates a real image which serves as the object for the second lens, and the image created by the second lens is the one a viewer sees. The final image is magnified, virtual and is inverted compared to the original object.
[16] A radioactive substance emits?
A.
alpha particle
B.
beta particle
C.
gamma particle
D.
all of the three
Ans:
all of the three
Explanation :
Radioactive substances are continually producing three kinds of dangerous radiation: alpha particles, beta particles and gamma rays. These types of radiation are invisible to the naked eye, and so you won't see a green glow.
[17] A single fixed pulley is used to draw water from a well because –
A.
efficiency is 100%
B.
velocity ratio is low
C.
mechanical advantage is high
D.
force is applied in a convenient direction
Ans:
force is applied in a convenient direction
Explanation :
A single fixed pulley is used to lift a load upwards by applying efforts downwards. The load and effort move equal distance but in opposite directions. This is convenient as to apply effort in downward direction. They are used on flag-poles and to draw water from a well.
[18] Hyperrnetropia or longsight can be corrected by using :
A.
Bifocal lenses
B.
Cylindrical lenses
C.
Concave lenses
D.
Convex lenses
Ans:
Convex lenses
Explanation :
It can be corrected with convex lenses in eyeglasses or contact lenses. Convex lenses have a positive dioptric value, which causes the light to focus closer than its normal range.
[19] Stars appear twinkling because of of light.
A.
Reflection
B.
Scattering
C.
Emission
D.
Absorption
Ans:
Scattering
Explanation :
The stars' light must travel through the Earth's multi-layered atmosphere, and as it does so it is refracted (bent) multiple times and in random directions. The phenomenon of random refraction appears to make the star wink as though it is in motion. It is this action that our eyes translate as twinkling.
[20] In mirrors the back surface is coated with a thin layer of :
A.
Mercury
B.
Silver
C.
Red oxide
D.
Silver nitrate
Ans:
Silver
Explanation :
In a spherical mirror, one of the two curved surfaces is coated with a thin layer of silver followed by a coating of red lead oxide paint. Thus, one side of the spherical minor is opaque and the other side is a highly polished reflecting surface.
[21] A bomb at rest explodes into a large number of tiny fragments. The total momentum of all the fragments –
A.
is zero
B.
depends on the total mass of all the fragments
C.
depends on the speeds of various fragments
D.
is infinity
Ans:
is zero
Explanation :
In an explosion, an internal impulse acts in order to propel the parts of a system (often a single object) into a variety of directions. After the explosion, the individual parts of the system (that is often a collection of fragments from the original object) have momentum.
[22] Sound energy passing per second through a unit area held perpendicular is called -
A.
Intensity
B.
Frequency
C.
Amplitude
D.
Quality
Ans:
Intensity
Explanation :
Sound energy passes through a unit area held perpendicular to the direction of propagation of sound waves is called intensity of sound.
[23] Which one of the following is used to remove Astigmatism for a human eye?
A.
Concave lens
B.
Convex lens
C.
Cylindrical lens
D.
Prismatic lens
Ans:
Cylindrical lens
Explanation :
A cylindrical lens is a lens which focuses light into a line instead of a point, as a spherical lens would.
[24] Speed of sound in air is unaffected by change in :
A.
Pressure
B.
Humidity
C.
Temperature
D.
Volume
Ans:
Pressure
Explanation :
The speed of sound in air depends on the density of air and the density of air depends on the temperature. The speed of sound is unaffected by pressure. If the atmospheric pressure changes, the speed of sound in air remains constant.
[25] The audio signals of TV are :
A.
Amplitude modulated
B.
Frequency modulated
C.
Unmodulated
D.
Velocity modulated
Ans:
Frequency modulated
Explanation :
In telecommunications and signal processing, frequency modulation (FM) conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant. In analogue television, the sound portion of a broadcast is invariably modulated separately from the video.
Explanation :
When Soaps and detergents are added to water, they weaken the strength of the skin on the water's surface due to surface tension by interfering with hydrogen bonding between water molecules. It happens because the polar end of the soap or detergent is also attracted to the water, thereby decreasing the surface tension.
[14] Small bubbles are perfectly spherical because of –
A.
Gravity
B.
Pressure
C.
Viscosity
D.
Surface tension
Ans:
Surface tension
Explanation :
Surface tension is responsible for the shape of liquid droplets. Although easily deformed, droplets of water tend to be pulled into a spherical shape by the cohesive forces of the surface layer. In the absence of other forces, including gravity, drops of virtually an liquids would be perfectly spherical. The spherical shape minimizes the necessary "wall tension" of the surface layer according to Laplace's law.
[15] The final image in a simple microscope is –
A.
real, diminished and inverted
B.
real, magnified and erect
C.
virtual, magnified and erect
D.
virtual, diminished and erect
Ans:
virtual, magnified and erect
Explanation :
A basic microscope is made up of two converging lenses. The first lens creates a real image which serves as the object for the second lens, and the image created by the second lens is the one a viewer sees. The final image is magnified, virtual and is inverted compared to the original object.
[16] A radioactive substance emits?
A.
alpha particle
B.
beta particle
C.
gamma particle
D.
all of the three
Ans:
all of the three
Explanation :
Radioactive substances are continually producing three kinds of dangerous radiation: alpha particles, beta particles and gamma rays. These types of radiation are invisible to the naked eye, and so you won't see a green glow.
[17] A single fixed pulley is used to draw water from a well because –
A.
efficiency is 100%
B.
velocity ratio is low
C.
mechanical advantage is high
D.
force is applied in a convenient direction
Ans:
force is applied in a convenient direction
Explanation :
A single fixed pulley is used to lift a load upwards by applying efforts downwards. The load and effort move equal distance but in opposite directions. This is convenient as to apply effort in downward direction. They are used on flag-poles and to draw water from a well.
[18] Hyperrnetropia or longsight can be corrected by using :
A.
Bifocal lenses
B.
Cylindrical lenses
C.
Concave lenses
D.
Convex lenses
Ans:
Convex lenses
Explanation :
It can be corrected with convex lenses in eyeglasses or contact lenses. Convex lenses have a positive dioptric value, which causes the light to focus closer than its normal range.
[19] Stars appear twinkling because of of light.
A.
Reflection
B.
Scattering
C.
Emission
D.
Absorption
Ans:
Scattering
Explanation :
The stars' light must travel through the Earth's multi-layered atmosphere, and as it does so it is refracted (bent) multiple times and in random directions. The phenomenon of random refraction appears to make the star wink as though it is in motion. It is this action that our eyes translate as twinkling.
[20] In mirrors the back surface is coated with a thin layer of :
A.
Mercury
B.
Silver
C.
Red oxide
D.
Silver nitrate
Ans:
Silver
Explanation :
In a spherical mirror, one of the two curved surfaces is coated with a thin layer of silver followed by a coating of red lead oxide paint. Thus, one side of the spherical minor is opaque and the other side is a highly polished reflecting surface.
[21] A bomb at rest explodes into a large number of tiny fragments. The total momentum of all the fragments –
A.
is zero
B.
depends on the total mass of all the fragments
C.
depends on the speeds of various fragments
D.
is infinity
Ans:
is zero
Explanation :
In an explosion, an internal impulse acts in order to propel the parts of a system (often a single object) into a variety of directions. After the explosion, the individual parts of the system (that is often a collection of fragments from the original object) have momentum.
[22] Sound energy passing per second through a unit area held perpendicular is called -
A.
Intensity
B.
Frequency
C.
Amplitude
D.
Quality
Ans:
Intensity
Explanation :
Sound energy passes through a unit area held perpendicular to the direction of propagation of sound waves is called intensity of sound.
[23] Which one of the following is used to remove Astigmatism for a human eye?
A.
Concave lens
B.
Convex lens
C.
Cylindrical lens
D.
Prismatic lens
Ans:
Cylindrical lens
Explanation :
A cylindrical lens is a lens which focuses light into a line instead of a point, as a spherical lens would.
[24] Speed of sound in air is unaffected by change in :
A.
Pressure
B.
Humidity
C.
Temperature
D.
Volume
Ans:
Pressure
Explanation :
The speed of sound in air depends on the density of air and the density of air depends on the temperature. The speed of sound is unaffected by pressure. If the atmospheric pressure changes, the speed of sound in air remains constant.
[25] The audio signals of TV are :
A.
Amplitude modulated
B.
Frequency modulated
C.
Unmodulated
D.
Velocity modulated
Ans:
Frequency modulated
Explanation :
In telecommunications and signal processing, frequency modulation (FM) conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant. In analogue television, the sound portion of a broadcast is invariably modulated separately from the video.
Explanation :
A basic microscope is made up of two converging lenses. The first lens creates a real image which serves as the object for the second lens, and the image created by the second lens is the one a viewer sees. The final image is magnified, virtual and is inverted compared to the original object.
[16] A radioactive substance emits?
A.
alpha particle
B.
beta particle
C.
gamma particle
D.
all of the three
Ans:
all of the three
Explanation :
Radioactive substances are continually producing three kinds of dangerous radiation: alpha particles, beta particles and gamma rays. These types of radiation are invisible to the naked eye, and so you won't see a green glow.
[17] A single fixed pulley is used to draw water from a well because –
A.
efficiency is 100%
B.
velocity ratio is low
C.
mechanical advantage is high
D.
force is applied in a convenient direction
Ans:
force is applied in a convenient direction
Explanation :
A single fixed pulley is used to lift a load upwards by applying efforts downwards. The load and effort move equal distance but in opposite directions. This is convenient as to apply effort in downward direction. They are used on flag-poles and to draw water from a well.
[18] Hyperrnetropia or longsight can be corrected by using :
A.
Bifocal lenses
B.
Cylindrical lenses
C.
Concave lenses
D.
Convex lenses
Ans:
Convex lenses
Explanation :
It can be corrected with convex lenses in eyeglasses or contact lenses. Convex lenses have a positive dioptric value, which causes the light to focus closer than its normal range.
[19] Stars appear twinkling because of of light.
A.
Reflection
B.
Scattering
C.
Emission
D.
Absorption
Ans:
Scattering
Explanation :
The stars' light must travel through the Earth's multi-layered atmosphere, and as it does so it is refracted (bent) multiple times and in random directions. The phenomenon of random refraction appears to make the star wink as though it is in motion. It is this action that our eyes translate as twinkling.
[20] In mirrors the back surface is coated with a thin layer of :
A.
Mercury
B.
Silver
C.
Red oxide
D.
Silver nitrate
Ans:
Silver
Explanation :
In a spherical mirror, one of the two curved surfaces is coated with a thin layer of silver followed by a coating of red lead oxide paint. Thus, one side of the spherical minor is opaque and the other side is a highly polished reflecting surface.
[21] A bomb at rest explodes into a large number of tiny fragments. The total momentum of all the fragments –
A.
is zero
B.
depends on the total mass of all the fragments
C.
depends on the speeds of various fragments
D.
is infinity
Ans:
is zero
Explanation :
In an explosion, an internal impulse acts in order to propel the parts of a system (often a single object) into a variety of directions. After the explosion, the individual parts of the system (that is often a collection of fragments from the original object) have momentum.
[22] Sound energy passing per second through a unit area held perpendicular is called -
A.
Intensity
B.
Frequency
C.
Amplitude
D.
Quality
Ans:
Intensity
Explanation :
Sound energy passes through a unit area held perpendicular to the direction of propagation of sound waves is called intensity of sound.
[23] Which one of the following is used to remove Astigmatism for a human eye?
A.
Concave lens
B.
Convex lens
C.
Cylindrical lens
D.
Prismatic lens
Ans:
Cylindrical lens
Explanation :
A cylindrical lens is a lens which focuses light into a line instead of a point, as a spherical lens would.
[24] Speed of sound in air is unaffected by change in :
A.
Pressure
B.
Humidity
C.
Temperature
D.
Volume
Ans:
Pressure
Explanation :
The speed of sound in air depends on the density of air and the density of air depends on the temperature. The speed of sound is unaffected by pressure. If the atmospheric pressure changes, the speed of sound in air remains constant.
[25] The audio signals of TV are :
A.
Amplitude modulated
B.
Frequency modulated
C.
Unmodulated
D.
Velocity modulated
Ans:
Frequency modulated
Explanation :
In telecommunications and signal processing, frequency modulation (FM) conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant. In analogue television, the sound portion of a broadcast is invariably modulated separately from the video.
Explanation :
A single fixed pulley is used to lift a load upwards by applying efforts downwards. The load and effort move equal distance but in opposite directions. This is convenient as to apply effort in downward direction. They are used on flag-poles and to draw water from a well.
[18] Hyperrnetropia or longsight can be corrected by using :
A.
Bifocal lenses
B.
Cylindrical lenses
C.
Concave lenses
D.
Convex lenses
Ans:
Convex lenses
Explanation :
It can be corrected with convex lenses in eyeglasses or contact lenses. Convex lenses have a positive dioptric value, which causes the light to focus closer than its normal range.
[19] Stars appear twinkling because of of light.
A.
Reflection
B.
Scattering
C.
Emission
D.
Absorption
Ans:
Scattering
Explanation :
The stars' light must travel through the Earth's multi-layered atmosphere, and as it does so it is refracted (bent) multiple times and in random directions. The phenomenon of random refraction appears to make the star wink as though it is in motion. It is this action that our eyes translate as twinkling.
[20] In mirrors the back surface is coated with a thin layer of :
A.
Mercury
B.
Silver
C.
Red oxide
D.
Silver nitrate
Ans:
Silver
Explanation :
In a spherical mirror, one of the two curved surfaces is coated with a thin layer of silver followed by a coating of red lead oxide paint. Thus, one side of the spherical minor is opaque and the other side is a highly polished reflecting surface.
[21] A bomb at rest explodes into a large number of tiny fragments. The total momentum of all the fragments –
A.
is zero
B.
depends on the total mass of all the fragments
C.
depends on the speeds of various fragments
D.
is infinity
Ans:
is zero
Explanation :
In an explosion, an internal impulse acts in order to propel the parts of a system (often a single object) into a variety of directions. After the explosion, the individual parts of the system (that is often a collection of fragments from the original object) have momentum.
[22] Sound energy passing per second through a unit area held perpendicular is called -
A.
Intensity
B.
Frequency
C.
Amplitude
D.
Quality
Ans:
Intensity
Explanation :
Sound energy passes through a unit area held perpendicular to the direction of propagation of sound waves is called intensity of sound.
[23] Which one of the following is used to remove Astigmatism for a human eye?
A.
Concave lens
B.
Convex lens
C.
Cylindrical lens
D.
Prismatic lens
Ans:
Cylindrical lens
Explanation :
A cylindrical lens is a lens which focuses light into a line instead of a point, as a spherical lens would.
[24] Speed of sound in air is unaffected by change in :
A.
Pressure
B.
Humidity
C.
Temperature
D.
Volume
Ans:
Pressure
Explanation :
The speed of sound in air depends on the density of air and the density of air depends on the temperature. The speed of sound is unaffected by pressure. If the atmospheric pressure changes, the speed of sound in air remains constant.
[25] The audio signals of TV are :
A.
Amplitude modulated
B.
Frequency modulated
C.
Unmodulated
D.
Velocity modulated
Ans:
Frequency modulated
Explanation :
In telecommunications and signal processing, frequency modulation (FM) conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant. In analogue television, the sound portion of a broadcast is invariably modulated separately from the video.
Explanation :
The stars' light must travel through the Earth's multi-layered atmosphere, and as it does so it is refracted (bent) multiple times and in random directions. The phenomenon of random refraction appears to make the star wink as though it is in motion. It is this action that our eyes translate as twinkling.
[20] In mirrors the back surface is coated with a thin layer of :
A.
Mercury
B.
Silver
C.
Red oxide
D.
Silver nitrate
Ans:
Silver
Explanation :
In a spherical mirror, one of the two curved surfaces is coated with a thin layer of silver followed by a coating of red lead oxide paint. Thus, one side of the spherical minor is opaque and the other side is a highly polished reflecting surface.
[21] A bomb at rest explodes into a large number of tiny fragments. The total momentum of all the fragments –
A.
is zero
B.
depends on the total mass of all the fragments
C.
depends on the speeds of various fragments
D.
is infinity
Ans:
is zero
Explanation :
In an explosion, an internal impulse acts in order to propel the parts of a system (often a single object) into a variety of directions. After the explosion, the individual parts of the system (that is often a collection of fragments from the original object) have momentum.
[22] Sound energy passing per second through a unit area held perpendicular is called -
A.
Intensity
B.
Frequency
C.
Amplitude
D.
Quality
Ans:
Intensity
Explanation :
Sound energy passes through a unit area held perpendicular to the direction of propagation of sound waves is called intensity of sound.
[23] Which one of the following is used to remove Astigmatism for a human eye?
A.
Concave lens
B.
Convex lens
C.
Cylindrical lens
D.
Prismatic lens
Ans:
Cylindrical lens
Explanation :
A cylindrical lens is a lens which focuses light into a line instead of a point, as a spherical lens would.
[24] Speed of sound in air is unaffected by change in :
A.
Pressure
B.
Humidity
C.
Temperature
D.
Volume
Ans:
Pressure
Explanation :
The speed of sound in air depends on the density of air and the density of air depends on the temperature. The speed of sound is unaffected by pressure. If the atmospheric pressure changes, the speed of sound in air remains constant.
[25] The audio signals of TV are :
A.
Amplitude modulated
B.
Frequency modulated
C.
Unmodulated
D.
Velocity modulated
Ans:
Frequency modulated
Explanation :
In telecommunications and signal processing, frequency modulation (FM) conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant. In analogue television, the sound portion of a broadcast is invariably modulated separately from the video.
Explanation :
In an explosion, an internal impulse acts in order to propel the parts of a system (often a single object) into a variety of directions. After the explosion, the individual parts of the system (that is often a collection of fragments from the original object) have momentum.
[22] Sound energy passing per second through a unit area held perpendicular is called -
A.
Intensity
B.
Frequency
C.
Amplitude
D.
Quality
Ans:
Intensity
Explanation :
Sound energy passes through a unit area held perpendicular to the direction of propagation of sound waves is called intensity of sound.
[23] Which one of the following is used to remove Astigmatism for a human eye?
A.
Concave lens
B.
Convex lens
C.
Cylindrical lens
D.
Prismatic lens
Ans:
Cylindrical lens
Explanation :
A cylindrical lens is a lens which focuses light into a line instead of a point, as a spherical lens would.
[24] Speed of sound in air is unaffected by change in :
A.
Pressure
B.
Humidity
C.
Temperature
D.
Volume
Ans:
Pressure
Explanation :
The speed of sound in air depends on the density of air and the density of air depends on the temperature. The speed of sound is unaffected by pressure. If the atmospheric pressure changes, the speed of sound in air remains constant.
[25] The audio signals of TV are :
A.
Amplitude modulated
B.
Frequency modulated
C.
Unmodulated
D.
Velocity modulated
Ans:
Frequency modulated
Explanation :
In telecommunications and signal processing, frequency modulation (FM) conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant. In analogue television, the sound portion of a broadcast is invariably modulated separately from the video.
Explanation :
A cylindrical lens is a lens which focuses light into a line instead of a point, as a spherical lens would.
[24] Speed of sound in air is unaffected by change in :
A.
Pressure
B.
Humidity
C.
Temperature
D.
Volume
Ans:
Pressure
Explanation :
The speed of sound in air depends on the density of air and the density of air depends on the temperature. The speed of sound is unaffected by pressure. If the atmospheric pressure changes, the speed of sound in air remains constant.
[25] The audio signals of TV are :
A.
Amplitude modulated
B.
Frequency modulated
C.
Unmodulated
D.
Velocity modulated
Ans:
Frequency modulated
Explanation :
In telecommunications and signal processing, frequency modulation (FM) conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant. In analogue television, the sound portion of a broadcast is invariably modulated separately from the video.
Explanation :
In telecommunications and signal processing, frequency modulation (FM) conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant. In analogue television, the sound portion of a broadcast is invariably modulated separately from the video.