Q. The unit of Stefan’s constant is
A) ${Wm}^{- 2}\ K^{- 1}$
B) $Wm\ K^{- 4}$
C) ${Wm}^{- 2}\ K^{- 4}$
D) ${Nm}^{- 2}\ K^{- 4}$
Explanation
According to Stefan’s law, the energy radiated per second or power radiated is given by $\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ P = \sigma AT^{4}$ $\therefore\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \sigma = \frac{P}{AT^{4}}$ Therefore, unit of $\sigma = \frac{W}{m^{2}K^{4}} = {Wm}^{- 2}K^{- 4}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.