Wave property of electrons implies that they will show diffraction effects. Davisson effects. Davisson and Germer demonstrated this by diffracting electrons from crystals. The law governing the diffraction from a crystal is obtained by requiring that electrons waves reflected from the planes of atoms in a crystal interfere constructively (see in figure)

Electrons accelerated by potential V are diffracted from a crystal. If `d = 1 Å` and `i = 30^(@)`, V should be about `(h = 6.6 xx 10^(-34) Js, m_(e) = 9.1 xx 10^(-31) kg, e = 1.6 xx 10^(-19)C)`

Options

A. `2000 V`
B. `50 V`
C. `500 V`
D. `1000 V`

Answer

B

Explanation

`2d cos I =n lambda implies 2d cos i=(h)/sqrt(meV)implies V=50` volt