Q 11-10-033NEETJEE MainEAMCET 2007 (Engineering)Easy
A black body radiates energy at the rate of $E$ watt/m$^2$ at a high temperature $T$ K. When the temperature is reduced to $\dfrac{T}{2}$ K, the radiant energy is
Answer: (D) $\dfrac{E}{16}$
Concept. Stefan's law: emitted power per unit area $E \propto T^4$.
Step 1. Halve $T$.
$$E' = E\left(\frac12\right)^4 = \frac{E}{16}$$
Answer. $\dfrac{E}{16}$ (Option D).
Solution by Sreeraj P, M.Sc Physics