$A$ hot and a cold body are kept in a vacuum,separated from each other. Which of the following causes a decrease in the temperature of the hot body?

Compared to a white-skinned person,what does a dark-skinned person experience?

The surface of a thermos flask is kept shiny because:

What is a perfect black body? Give examples.

$A$ piece of blue glass heated to a high temperature and a piece of red glass at room temperature are taken inside a dimly lit room. Then:

The coefficient of absorption $(a)$ and the coefficient of reflection $(r)$ of a thin uniform plate are $0.77$ and $0.17$ respectively. If $250 \ kcal$ of heat is incident on the surface of the plate,the quantity of heat transmitted $(t)$ is: (in $kcal$)