Question

If temperature of sun is decreased by $1\%$ then the value of solar constant will change by

• A. $2\%$
• B. $-4\%$
• C. $-2\%$
• D. $4\%$

Answer 1

Answer: (B)

$-4\%$

Solar constant $=G=\sigma T^4\left[\frac{4\pi R^2}{4\pi O^2}\right]$
$\therefore$ change of G w.r.t $O$ on both sides
$△G=4\sigma T^3△T\left[\frac{4\pi R^2}{4\pi O^2}\right]$
$\frac{△G}{G}=\frac{4△T}{T}=-4\%$