Ans: \((\) A)
$$
\begin{aligned} \text { Option }(\mathrm{a}): E &=6.626 \times 10^{-34} \mathrm{~J} . \mathrm{s} \times 3 \times 10^{8} \mathrm{~m} / \mathrm{s} \times \frac{1}{300 \times 10^{-9} \mathrm{~m}} \\ &=6.626 \times 10^{-19 \mathrm{~J}} \end{aligned}
$$
Option (b) : \(E=6.626 \times 10^{-34} \mathrm{~J} . \mathrm{s} \times 3 \times 10^{8}=1.9878 \times 10^{-25} \mathrm{~J}\)
Option (c): \(E=6.626 \times 10^{-34} \mathrm{~J} . \mathrm{s} \times 3 \times 10^{8} \mathrm{~m} / \mathrm{s} \times 30 \times 10^{2} \mathrm{~m}^{-1}=5.9634 \times 10^{-22} \mathrm{~J}\)
Option (d) : \(E=6.626 \times 10^{27} \mathrm{~J}\)
Among these, maximum energy is \(6.626 \times 10^{19} \mathrm{~J}\)