$A$ hot body will radiate heat most rapidly if its surface 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?

$A$ body has a black spot on it. When the body is heated and taken into a dark room,the black spot glows more brightly. This can be explained by which of the following?

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?

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

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