$x$ joule of heat is incident on a body. Out of it, the total heat reflected and transmitted by it is $y$ joule. The absorption coefficient of the body is

Three identical metal spheres (of same surface area) have red,black,and white colors and they are heated up to the same temperature. They are allowed to cool. Arrange them from maximum rate of cooling to minimum rate of cooling.

Three very large plates of the same area are kept parallel and close to each other. They are considered as ideal black surfaces and have very high thermal conductivity. The first and third plates are maintained at temperatures $2\ T$ and $3\ T$ respectively. The temperature of the middle (i.e.,second) plate under steady-state condition is

$A$ body,which emits radiations of all possible wavelengths,is known as ...........

Which instrument is used to detect infrared rays?

Compared to a white-skinned person,what does a dark-skinned person experience?