The first order reflection of a beam of X-rays of wavelength 1.54 Ã… from the (100) face of a crystal of the simple cubic type occurs at an angle of `11.29^(@)` . Calculate the length of the unit cell.

Explanation

We have,
`nlambda = 2d sin theta` ………..(Eqn. 6)
`1 xx (1.54 xx 10^(-8)) cm = 2 xx d xx sin 11.29`
`d=3.68 xx 10^(-8) cm`
Further, `d= a/sqrt(h^(2) + k^(2) + l^(2))`………..(Eqn. 2)
or `3.68 xx 10^(-8) = a/sqrt(1^(2) + 0^(2) + 0^(2))`
or `a=3.68 xx 10^(-8)` cm