Question

The momentum of a photon of energy 1MeV, in kg/m/s, will be :

• A. ${10}^{-22}$
• B. $0.33\times {10}^6$
• C. $5\times {10}^{-22}$
• D. $7\times {10}^{-24}$

Answer 1

The correct option is C $5\times {10}^{-22}$

The momentum of photon is given by

$p=\frac{E}{c}$

where, E is the energy of photon(in eV) and c is the velocity of light , $c=3\times {10}^{8}m{s}^{-1}$.

$p=\frac{1\times {10}^6\times 1.6\times {10}^{-19}}{3\times {10}^8}$

$p=0.533\times {10}^{-21}$

$p=5\times {10}^{-22}kgs{m}^{-1}$

So, the answer is option (C).