Question

Calculate the linear momentum of photons of wavelength 740 nm. What speed does anelectron need to travel to have the same linear momentum?

Answer 1

Answer:

v = 9.824 x 10³ m/s

Explanation:

given,

Linear momentum of photon,λ = 740 n m

for photon,

$p=\dfrac{h}{\lambda}$

h is the planks constant

P is the momentum

$p=\dfrac{6.626\times 10^{-34}}{740\times 10^{-10}}$

      p = 8.95 x 10⁻²⁷ kg.m/s

For electron

p = m v

mass of electron = 9.11 x 10⁻³¹ Kg

$v = \dfrac{8.95\times 10^{-27}}{9.11\times 10^{-31}}$

v = 9.824 x 10³ m/s

hence, the velocity of electron is equal to   v = 9.824 x 10³ m/s