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Unit of Stefan's constant is : -
A
Watt m$^2$ K$^4$
B
Watt m$^2$/K$^4$
C
Watt/m$^2$ K
D
Watt/m$^2$ K$^4$
Detailed Solution
Stefan's law: the energy radiated per unit area per second, $E = \sigma T^4$.
$\sigma = \dfrac{E}{T^4}$, where E is in watt per square metre (W m$^{-2}$) and T in kelvin.
Unit of $\sigma$ = $\dfrac{\text{W m}^{-2}}{\text{K}^4}$ = W m$^{-2}$ K$^{-4}$, i.e. Watt/m$^2$ K$^4$.
Its value is $5.67 \times 10^{-8}$ W m$^{-2}$ K$^{-4}$.
$\sigma = \dfrac{E}{T^4}$, where E is in watt per square metre (W m$^{-2}$) and T in kelvin.
Unit of $\sigma$ = $\dfrac{\text{W m}^{-2}}{\text{K}^4}$ = W m$^{-2}$ K$^{-4}$, i.e. Watt/m$^2$ K$^4$.
Its value is $5.67 \times 10^{-8}$ W m$^{-2}$ K$^{-4}$.