Question

Assume that Solar constant is $1.4kW/m^2$, radius of sun is $7\times 10^{5}km$ and the distance of earth from centre of sun is $1.5\times 10^{8}km$. Stefan's constant is $5.67\times 10^{-8}W{m}^{-2}{K}^{-4}$, find the approximate temperature of sun

• A. 5800 K
• B. 16000 K
• C. 15500 K
• D. 8000 K

Answer 1

Answer: (A)

$S={\left[\frac{R}{r}\right]}^2\sigma T^4$
$1.4\times 10^3={\left[\frac{7\times 10^5}{1.5\times 10^8}\right]}^2\times 5.67\times 10^{-8}\times T^4$
$T=5800K$