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

What is the speed of heat radiation equal to?

Two thermometers $A$ and $B$ are exposed to sunlight. The bulb of $A$ is painted black,but that of $B$ is not painted. Which of the following statements is correct regarding this case?

The graph shown in the adjacent diagram represents the variation of temperature $(T)$ of two bodies,$x$ and $y$,having the same surface area,with time $(t)$ due to the emission of radiation. Find the correct relation between their emissivities $(e)$ and absorptive powers $(a)$.

For a perfectly black body,the coefficient of emission (emissivity) is:

For an opaque body,the coefficient of transmission is: