GATE-2018 (24) :Wyllie – Time average equation

 Q) What will happen to the maximum value of spectral energy density of a blackbody when its temperature is doubled? 

Solution:

(Thanks to Rajkumar, AKNU)

    From Stefan -Boltzmann Law

    $E=\sigma T^{4}$    

Where, Stefan Boltzmann constant is $\sigma=5.67\times10^{-8}\frac{w}{m^{2}k^{4}}$

if T= 2T 

 Then E=?

  $E=\sigma (2T)^{4} =\sigma16T^{4}$

So, Radiant Energy increases by 16 times.