Question

1. Compare the de Broglie wavelength of a 0.015-kg ball moving at 40 m/s to that of an electron which has a speed of 0.0073c. Given: mass of electron = 9.11 x 10^-31kg, speed of light = c = 3 x 10⁸ m/s.

Answer 1

de Broglie wavelength of a mass ( m ) moving with a velocity ( v ) is given by,

  

where, h = Planck's Constant =  

For de Broglie wavelength of a ball of mass m = 0.015 kg , moving with a velocity v = 40 m/s,

  

For de Broglie wavelength of a ball of mass m = 9.11 x 10^(-31) kg ,

moving with a velocity, v = 0.0073c => v = 0.0073 x 3 x 10^(8) => v = 2.19 x 10^(6) m/s

  

  

Comparing

That is the de Broglie wavelength for the electron is 3 x 10^(23) times that of the ball.

De broglie wavelength for a smaller body ( microscopic ) is much significant than a heavier body ( macroscopic )