Power \(P=\frac{\text { nhc }}{\lambda t} \Rightarrow n=\frac{p \lambda t}{h c}\)
\(=0.5 \times 10^{3} \times \) \(\frac{{660 \times {{10}^{ - 9}} \times 60 \times {{10}^{ - 3}}}}{{6.6 \times {{10}^{ - 34}} \times 3 \times {{10}^8}}}\)
\(=100 \times 10^{18}=10^{20}\)
$E$ ( $eV$ માં) $ = \frac{{1237}}{{\lambda \left( {in\,nm} \right)}}$