Practice MCQ Questions and answers on Physics-GK

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.

The earth is a good absorber and good radiator of heat.

According to Newton’s law of cooling, the rate of loss of heat of a body is directly proportional to the difference between the temperature of hot body and temperature of the surroundings, provided that the difference in temperature is small enough.

The word ''insolation' means incoming solar radiation.

Tap water is placed in an open pad and allowed to evaporate. After some time the temperature of water decreases slightly.

Heat is transferred in the liquid and gases from a region of higher temperature to a region of lower temperature. Convection heat transfer occurs partly due to the actual movement of molecules or due to the mass transfer.

Energy travels from Sun to Earth through radiation.

In convection, hot air rises from the Earth's surface and becomes cold at higher altitude because of lower temperature there. As it cools, it sinks down to the surface of the Earth. On reaching Earth, it warms again and rises up again. The main reason for this phenomenon is - sinking cold air pushes the warm air up.

Land breeze occur during fall and winter.

Desert coolers are based on the simple principle that when unsaturated air comes in contact with water, the water evaporates. In the process, the moisture content of air increases, while its temperature decreases. The resulting cold but moist air is used for providing cooling.