2.59 If the velocity of the electron in Bohr’s first orbit is 2.19 × 106 ms–1, calculate the
de Broglie wavelength associated with it.

According to de Broglie’s equation, λ = h/mv
Where, λ = wavelength associated with the
electron h = Planck’s constant
m = mass of electron
v = velocity of electron
Substituting the values in the expression of λ:
λ = 6.626 x 10-34 Js9.10939 x 1031 kg2.19 x 106 m/s
= 3.32 x 10-10 m = 3.32 x 10-10 m x 100100
= 332 x 10-12 m
λ = 332 pm
 Wavelength associated with the electron = 332 pm