Q. If the sun’s surface radiates heat at $6.3 \times 10^{7}Wm^{- 2}$. Calculate the temperature of the sun assuming it to be a black body $(\sigma = 5.7 \times 10^{- 8}Wm^{- 2}K^{- 4})$
A) $5.8 \times 10^{3}K$
B) $8.5 \times 10^{3}K$
C) $3.5 \times 10^{8}K$
D) $5.3 \times 10^{8}K$
Explanation
(a) From Stefan’s law $E = \sigma T^{4}$
$T^{4} = \frac{E}{\sigma} = \frac{6.3 \times 10^{7}}{5.7 \times 10^{- 8}} = 1.105 \times 10^{15} = 0.1105 \times 10^{16}$
$T = 0.58 \times 10^{4}K = 5.8 \times 10^{3}K$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.