For a perfect black body,the absorption coefficient is

At a high temperature,a body emits radiation of wavelengths $\lambda_1, \lambda_2, \lambda_3,$ and $\lambda_4$ only. At a lower temperature,which of the following wavelengths will it absorb?

The following graph shows the correct variation in the intensity of heat radiations emitted by a black body with respect to frequency at different fixed temperatures. Identify the correct graph.

Thermal radiation travels at the speed of . . . . . . .

$A$ body is in thermal equilibrium with its surroundings. This is because .....

When red glass is heated in a dark room,it will appear: