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

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

$Assertion :$ $A$ 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.

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

In which process is the rate of transfer of heat maximum?

The spectrum of black body radiation is a ...... .