Question

Calculate the wavelength of an electron moving with a velocity of $2.05×10^7 \ ms^{–1}$.

Answer 1

According to de Broglie's equation,
$λ =\frac {h}{mv}$
Where,
λ = wavelength of moving particle
m = mass of particle
v = velocity of particle
h = Planck's constant
Substituting the values in the expression of λ :
$λ = \frac {6.626×10^{-34} Js }{(9.10939×10^{-31} kg)(2.05×10^7\ ms^{ -1})}$
$λ = 3.548×10^{-11}\ m$

Hence, the wavelength of the electron moving with a velocity of $2.05×10^7 \ ms^{-1}$ is $3.548×10^{-11}\ m$.