# Physics Questions and Answers – Davisson and Germer Experiment

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This set of Physics Multiple Choice Questions & Answers (MCQs) focuses on “Davisson and Germer Experiment”.

1. Which theory is confirmed by the Davisson – Germer experiment?
a) de – Broglie theory
b) Newton’s theory
c) Einstein’s theory
d) Planck’s theory

Explanation: Davisson and Germer experiment proves the concept of wave nature of matter particles. The Davisson–Germer experiment provides a critically important confirmation of the de-Broglie hypothesis, which said that particles, such as electrons, are of dual nature.

2. Which of the following is used in the Davisson – Germer experiment?
a) Double slit
b) Single slit
c) Electron gun
d) Electron microscope

Explanation: Davisson – Germer experiment uses an electron gun to produce a fine beam of electrons which can be accelerated to any desired velocity by applying a suitable voltage across the gun. The others mentioned do not find an application here.

3. Which crystal is used in the Davisson – Germer experiment?
a) Aluminum
b) Nickel
c) Cobalt
d) Zinc

Explanation: The crystal used in the Davisson – Germer experiment is nickel. A fine beam of electrons is made to fall on the surface of the nickel crystal. As a result, the electrons are scattered in all directions by the atoms of the crystal.

4. Intensity is different for different angles of scattering in the Davisson – Germer experiment.
a) True
b) False

Explanation: Yes, this statement is true. When the graphs are drawn showing the variation of intensity of the scattered electrons with the angles of scattering at different accelerating voltages, it is found that the intensity is different for different angles of scattering.

5. Identify the expression for Bragg’s law from the following.
a) 2d cos⁡θ=nλ
b) 2d sin⁡θ=nλ
c) 2d sinθ=$$\frac {n}{\lambda }$$
d) 2d cosθ⁡=$$\frac {n}{\lambda }$$

Explanation: Bragg’s law is a special case of Laue diffraction, it gives the angles for coherent and incoherent scattering from a crystal lattice. The expression for Bragg’s law is given as:
2d sin⁡θ=nλ 