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

When we enter an air-conditioned room,we feel cold. This can be explained by:

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

Which of the following statements is true for a perfectly black body?

Inside a closed furnace held at a temperature of $400\, K,$ we have a black body. $A$ hole of area $10\, cm^2$ is opened in the furnace so that sunlight starts falling on the black body. The intensity of sunlight is $2000\, W/m^2.$ In the steady state:

The relation between emissivity $e$ and absorptive power $a$ for a black body is: