Question

The unit of Stefan's constant is

• A. $W{m}^{-2}{K}^{-1}$
• B. $Wm{K}^{-4}$
• C. $W{m}^{-2}{K}^{-4}$
• D. $N{m}^{-2}{K}^{-4}$

Answer 1

Answer: (C)

According to Stefan's law, the energy radiated per second or power radiated is given by $P=\sigma A{T}^4$ $\therefore$ $\sigma =\frac{P}{A{T}^4}$ Therefore, unit of $\sigma =\frac{W}{m^2{K}^4}=W{m}^{-2}{K}^{-4}$