Question

Sun radiates energy at the rate of $3.6\times 10$${}^{26}$ Joule/s. The rate of decrease in mass of the sun is (in kgs${}^{-1}$)

• A. $12\times 10$${}^{10}$
• B. $1.3\times 10$${}^{20}$
• C. $4\times 10$${}^9$
• D. $3.6\times 10$${}^{36}$

Answer 1

The correct option is C $4\times 10$${}^9$

Energy radiated per second $=3.6\times {10}^{26}\frac{J}{s}$
Mass changing into this energy per second $=\frac{E}{c^2}=\frac{3.6\times {10}^{26}\frac{J}{S}}{(3\times {10}^8{)}^2\frac{m^2}{s^2}}$$=4\times {10}^9\frac{kg}{s}$