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

Explanation

For an electron
`(1)/(2) mv^(2) = eV`
where v in the accelerating portential
`lambda = (h)/("mu")`
`:. (1)/(2)m((k)/(m lambda))^(2) = eV`
`:. V = (1)/(2) xx (h^(2))/(m lambda^(2)e)`, subatituting all value , we get
`= (1 xx (6.626 xx 10^(-34))^(2))/( 2 xx 9.108 xx 10^(-13) xx (1.54 xx 10^(-19))^(2) xx 1.602 xx 10^(-19))`