An electron beam can undergo defraction by crystals .Through what potential should a beam of electrons be accelerated so that its wavelength becomes equal to `1.54 Å`

Options

A. `54.3 volt`
B. `63.3 volt`
C. `66.2 volt`
D. None of these

Answer

2

Explanation

For an electron `1/2 m u^(2)=eV` " " and `lambda=h/(m u)`
Thus, `1/2 m=(h^(2))/(m^(2)lambda^(2))=eV`
or `V=1/2h^(2)/(mlambda^(2)e)=(1xx(6.62xx10^(-34))^(2))/(2xx9.108xx10^(-31)(1.54xx10^(-10))^(2)xx1.602xx10^(-19))=63.3 volt.`