Question

Assuming that the smallest measurable wavelength in an experiment is 0.410 fm (femtometers), what is the maximum mass of an object traveling at 787 m·s–1 for which the de Broglie wavelength is observable?

Answer 1

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

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

λ = wave length = 0.410 fm = 0.410 x10^-15 m

m = mass of object = ?

v = velocity of object = 787 m/s

Plug the values we get   m = h / v λ

                                       = ( 6.625x 10^-34 Js) / ( 787 (m/s)x 0.410 x10^-15 m)

                                         = 2.05x10^-21 kg

Therefore the maximum mass of object is 2.05x10^-21 kg