According to Kirchhoff's law,the ratio of emissive power to absorptive power for all bodies is:

The following figure shows two air-filled bulbs connected by a $U$-tube partly filled with alcohol. One bulb is painted black and the other is painted white (or silver/shiny). What happens to the levels of alcohol in the limbs $X$ and $Y$ when an electric bulb placed midway between the two bulbs is lighted?

About black body radiation,which of the following is the wrong statement?

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?

$A$ total radiation of $400 \ J$ is incident on a body. If $20\%$ of the radiation is reflected and $120 \ J$ is absorbed,find the percentage of the transmittive power.

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