As compared to a person with white skin,a person with black skin will experience:

The absorption coefficient of an open window is:

The sun radiates electromagnetic energy at the rate of $3.9 \times 10^{26} \ W$. Its radius is $6.96 \times 10^8 \ m$. The intensity of sunlight at the solar surface will be (in $W/m^2$):

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?

$A$ solid cylinder of length $L$ and radius $r$ is heated up to the same temperature as that of a cube of edge length $a$. If both have the same material,volume,and are allowed to cool under similar conditions,then the ratio of the amount of radiation emitted will be (Neglect radiation emitted from the flat surfaces of the cylinder).

What are heat rays?