Question

5. (5)

(a) Describe the de Broglie Model (also known as the de Broglie-Bohr Model) of the hydrogen atom.

(b) What was its motivation? (To address what problem was it proposed?)

(c) What drawbacks did it still have when it was proposed?

Answer 1

a) One of the postunlates in boh'r model was that the angular momentum of an electron around the nucleus of an atom is an integral multiple of h/2? (where ‘h’ is Planck's constant).” That is to say that, electrons can follow only those paths where its angular momentum is equal to h/2? multiplied by an integer. However, Bohr was unable to prove this postulate of his.

At this, moment, de broglie came up with an explanation. De Broglie realized that if we use the wavelength associated with the electron, and assume that an integral number of wavelengths must fit in the circumference of an orbit, we get the same quantized angular momenta that Bohr did. Although de Broglie's equation justifies Bohr's quantization assumption, it also demonstrates a deficiency of Bohr's model

b) It was proposed to present the dual nature of the quantized particle. The de Broglie equation relates a moving particle's wavelengthwith its momentum.

c) Limitation of de Broglie equation is that it is good work on microscopic particle like electron ,proton and neutron but it fails in case of large size object it gets fail because they have more mass and their wavelength become smaller and smaller.