Question

An electron has a de Broglie wavelength of 215 nm, what is the speed of the electron?

Answer 1

According to de Broglie wave length, = h/mv
Where

h = plank's constant = 6.625x 10^-34 Js

= wave length = 215 nm = 215 x10^-9 m

m = mass of electron = 9.1x10^-31 kg

v = velocity of object = ?

Plug the values we get   v = h / m

                                     = ( 6.625x 10^-34 Js) / ( 9.1x10^-31 kgx 215 x10^-9 m)

                                     = 3386 m/s

Therefore the speed of electron is 3386 m/s