The momentum of a photon of frequency 5×10^14 Hz, is

The correct answer is Option (3) → \( 1.1\times10^{-27}\,\mathrm{J\,s\,m^{-1}} \)

A photon of frequency \( \nu \) has energy \( E = h\nu \) and momentum \( p = E/c = h\nu/c \) (equivalently \( h/\lambda \)).

    \( h = 6.63\times10^{-34}\,\mathrm{J\,s} \)
    \( \nu = 5\times10^{14}\,\mathrm{Hz} \)
    \( c = 3\times10^{8}\,\mathrm{m\,s^{-1}} \)

    \( \displaystyle p = \frac{h\nu}{c} = \frac{(6.63\times10^{-34})(5\times10^{14})}{3\times10^{8}}\,\mathrm{J\,s\,m^{-1}} \)

    \( \displaystyle p = \frac{3.315\times10^{-19}}{3\times10^{8}} \approx 1.1\times10^{-27}\,\mathrm{J\,s\,m^{-1}} \)