Question

Which one of the following statements is not true about de-Broglie waves ?

• A. All atomic particles in motion have waves of a definite wavelength associated with them
• B. The higher the momentum, the longer is the wave-length
• C. The faster the particle, the shorter is the wave-length
• D. For the same velocity, a heavier particle has a shorter wavelength

Answer 1

Answer: (B)

As, $\lambda= h / p = h / mv$
where, $h$ = Planck's constant, $\lambda=$ wavelength, $p=m v=$ momentum
It is shown that wavelength $\lambda$ is inversely proportional to the momentum. Hence, lighter the momentum, lesser will be the wavelength.