What will be the momentum of a photon of energy 0.1 MeV in SI unit?

The correct answer is Option (3) → \( 5.33 \times 10^{-23} \)

A photon has energy \( E = pc \), so its momentum is \( p = E/c \). The energy must first be converted from MeV to joules.

    \( \displaystyle E = 0.1\,\mathrm{MeV} = 0.1\times10^{6} \times 1.6\times10^{-19}\,\mathrm{J} = 1.6\times10^{-14}\,\mathrm{J} \)

    \( \displaystyle p = \frac{E}{c} = \frac{1.6\times10^{-14}\,\mathrm{J}}{3\times10^{8}\,\mathrm{m\,s^{-1}}} = 5.33\times10^{-23}\,\mathrm{kg\,m\,s^{-1}} \)