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

Options

(a) 5 x 10⁻²²
(b) 0.33 x 10⁶
(c) 7 x10⁻²⁴
(d) 10⁻²²

Correct Answer:

5 x 10⁻²²

Explanation:

Energy of photon E = 1 MeV

Momentum of photon p = E / c

p = E / c = (1 × 10⁶ × 1.6 × 10⁻¹⁹J) / 3 × 10⁸ ms⁻¹

= 0.53 × 10⁻²¹ = 5 × 10⁻²² kg m/s.