Q. A black body is heated from 27$℃$ to 927$℃$. The ratio of radiation emitted will be
A) 1:4
B) 1:8
C) 1:16
D) 1:256
Explanation
(d) According to Stefan’s law
$E \propto T^{4}\ \ \ \ \ or\ \ \ \ \ \ \ \ \ \ E = \sigma T^{4}$
Where $\sigma$ is Stefan’s constant. It’s value is
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ = 5.67 \times 10^{- 8}\ Wm^{- 2}K^{- 4}$
Here, $T_{1} = 27 + 273 = 300\ K$
$T_{2} = 927 + 273 = 1200\ K$
$\therefore$ $\frac{E_{1}}{E_{2}} = \left( \frac{300}{1200} \right)^{4} = 1:256$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.