b
\(\,I\,\, = \,\, \frac{E}{{At}}\,\, = \,\,1.4\,\, \times \,\,\,{10^3}\,\,watt\,/\,\,{m^2}\)

\(\therefore\) પ્રતિ સેકન્ડ ઊત્સર્જાતી ઊર્જા \(= I × A = I (4\pi r^2)\)

\(E/t = 1.4 × 103 ×4p ×(1.5 × 10^{11})^2\)

\(=  1.4 × 4p × 1.5 × 1.5 × 10^{25} = 39.56 × 10^{25}\, Joule/sec.\)

\(  E\,\, = \,\,\Delta \,m{c^2}\,\, \Rightarrow \,\,\frac{E}{t}\,\, = \,\,\frac{{\Delta \,m{c^2}}}{t}\)

\(  \frac{{\Delta \,m}}{t}\,\, = \,\,\frac{{(E/t)}}{{{c^2}}}\, = \,\,\frac{{39.56\,\, \times \,\,{{10}^{25}}}}{{9\,\, \times \,\,{{10}^{16}}}} \)

તેથી પ્રતિદિન \( = \,\,\,\frac{{39.56\,\, \times \,\,1{0^{25}}}}{{9\,\, \times \,\,{{10}^{16}}}}\,\, \times \,\,86400\,\,\)

\(= \,\,3.8\,\, \times \,\,{10^{14}}\,kg.\)