GK INFOPEDIA

[1] The phenomenon of radioactivity was discovered by – A. Marie Curie B. Pierre Curie C. Henri Becquerel D. J.J. Thomson Ans: Henri Becquerel Explanation : French physicist Henri Becquerel discovered radioactivity by accident in 1896 when a piece of uranium left in a dark desk drawer made an image on photographic plates. The husband […]

[1] Which of the following are methods of heat transfer? A. Convection B. Evaporation C. Revolution D. Thermal Expansion Ans: Convection Explanation : Convection is the transfer of heat from one place to another by the movement of fluids. It is usually the dominant form of heat transfer (convection) in liquids and gases. Although often […]

[1] A gap is left between two rails of a railway track to accommodate of the metal. A. areal expansion B. volume expansion C. liner expansion D. apparent expansion Ans: liner expansion Explanation : The volume of materials changes depending on current temperature. Usually heat makes them expand, and cold leads them to contract. To […]

[1] Stereo was invented by . A. John Barber B. Tim Berners-Lee C. Alan Blumlein D. David Brewster Ans: Alan Blumlein Explanation : Modern stereophonic technology was invented in the 1930s by British engineer Alan Blumlein at Electric and Musical Industries in London. Modern stereophonic technology was invented in the 1930s by British engineer Alan […]

[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 […]

[1] An ice block with a piece of lead embedded in it floats in water. If ice melts the water level – A. Rises B. Falls C. Remains same D. Falls first and them rises Ans: Falls Explanation : If r1 is the density of the lead piece of volume v, the volume of water […]

[1] Which one among the following substances evolved heat when dissolved in water? A. Glucose B. Fructose C. Quick lime D. Salt peter Ans: Quick lime Explanation : Quicklime is a widely used chemical compound. It is a white, caustic, alkaline, crystalline solid at room temperature. When limestone is heated, at about 1000° C it […]

[1] The period of revolution of a geostationary satellite is – A. 365 days B. 30 days C. 24 hours D. changing continuously Ans: 24 hours Explanation : A geosynchronous satellite is a satellite in geosynchronous orbit, with an orbital period the same as the Earth’s rotation period. Such a satellite returns to the same […]

[1] Earth is also known as – A. Orange planet B. Green planet C. Blue planet D. Yellow planet Ans: Blue planet Explanation : Planet Earth has been called the “Blue Planet” due to the abundant water on its surface. Here on Earth, we take liquid water for granted; after all, our bodies are mostly […]

[1] If cream is removed from milk, its density – A. Increases B. Decreases C. Remains the same D. May increase or decrease Ans: Increases Explanation : The density of pure fresh milk being on the average 1.032, while the density of fat globules is about 0.86. It follows that the removal of cream will […]