Q. Suppose the sun expands so that its radius becomes 100 times its present radius and its surface temperature becomes half of its present value. The total energy emitted by it then will increase by a factor of
A) $10^{4}$
B) 625
C) 256
D) 16
Explanation
(b) $\frac{Q_{2}}{Q_{1}} = \left( \frac{r_{2}^{2}}{r_{1}^{2}} \right)^{2} \times \left( \frac{T_{2}}{T_{1}} \right)^{4} = \left( \frac{100}{1} \right)^{2} \times \left( \frac{1}{2} \right)^{4} = 625$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.