Practice MCQ Questions and answers on Physics-GK

Ice packed in sawdust does not melt quickly because it provides insulation.

Ice packed in sawdust does not melt quickly because it provides insulation.

The usual cause of sea breeze is the difference in specific heat capacity between land and water Land heats and cools more quickly than water.

The outside surface of a utensil used for heating is coated black so that it may absorb more heat and make heating quicker. This is because black surface is a good absorber of heat.

Heat transfer by radiation depends upon all of the above.

A white and smooth surface is bad absorber and good reflector of heat.

It is evident that the atmosphere is primarily heated from below by radiation from the heated Earth surface.

The direction of heat flow between two objects depends on their temperatures. Heat always flows from a body at higher temperature to a body at a lower temperature.

Cotton clothes are thin and do not have space in which air can be trapped. Thus, cotton clothes do not prevent heat coming out of our body. Woollen clothes keep us warm during winter because wool is a poor conductor of heat and it has air trapped in between the fibres.

Hot water is poured simultaneously in four metallic tumblers painted outside with different paints. After some time the water will be found to have cooled most in the tumbler painted rough black. Black surfaces are good emitters of heat.