A proton of mass '\({m}_{p}\)' has same energy as that of a photon of wavelength '\(\lambda\)'. If the proton is moving …

\begin{equation}
\frac{1}{c} \sqrt{\frac{E}{m_p}}
\end{equation}

\begin{equation}
\frac{1}{c} \sqrt{\frac{E}{2 m_p}}
\end{equation}

\begin{equation}
\frac{1}{c} \sqrt{\frac{2 \mathrm{E}}{\mathrm{~m}_{\mathrm{p}}}}
\end{equation}

\begin{equation}
\frac{1}{2 c} \sqrt{\frac{\mathrm{E}}{\mathrm{~m}_{\mathrm{p}}}}
\end{equation}