### The Required de Broglie Wavelength:

A photon of light of frequency has the momentum,
The wavelength of a photon is, therefore, specified by its momentum according to the relation,

de Broglie suggested that the above equation is applicable for any material particles as well as photons. If the mass of a moving particle is m and velocity is v, then its momentum is p = mv and its de Broglie wavelength is accordingly,

If the particle is charged of charge q and accelerated through potential difference of volt V, the K.E.

Thus, the de Broglie wavelength for a charged particle of charge q which accelerating through potential difference of volt V is,