The rate of emission of a body doubles when its temperature is increased by $10^{\circ}C$. If the temperature of the body is increased from $10^{\circ}C$ to $100^{\circ}C$,the rate of emission increases by a factor of:

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 $(a)$.

In the rainy season,on a clear night,the black seat of a bicycle becomes wet because:

$Assertion :$ $A$ body that is a good radiator is also a good absorber of radiation at a given wavelength.
$Reason :$ According to Kirchhoff's law,the absorptivity of a body is equal to its emissivity at a given wavelength.

If there were no atmosphere on Earth,its temperature would be ...... .

Which of the following is best close to an ideal black body?