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100 W/m2 of solar energy is received by the Earth. If all the energy was to be absorbed by a bucket of water (mass 30 kg) in 30 minutes, then the rise in temperature of water will be
Power = 100 W/m2
Mass of water = 30 kg
Time = 30 minutes
Specific Heat of Water = 4200 J/kg °C
Heat Generated = Mass × Specific Heat × Temperature Rise.
Heat Generated = Power × time
Mass × Specific Heat × Temperature Rise = Power × time
Temperature Rise = 1.43 °C
So correct answer is C.
When the material P mined from the earth is heated strongly in an insufficient supply of air, it produces a solid fuel Q which mainly consist of carbon. When another material R obtained from trees is heated in an insufficient supply of air, it produces another solid fuel S which also consists mainly of carbon. Then, which of the following is true?