Question

The wavelength of `k_(alpha) ` X- rays produced by an X - rays tube is `0.76 Å` . The atomic number of the anode material of the tube is …….

Answer 1

`K_(alpha)` X-ray are produced when an electron makes a transition from `n = 2 to n = 1` to fill a vacancy in `K` shell . The wavelength of X-ray lines is given by
`(1)/(lambda_(K_alpha)) = R(Z - 1)^(2) ((1)/(1^(2)) - (1)/(2^(2))) = (3)/(4) R(Z - 1)^(2)` or `(Z - 1)^(2) = (4)/(3 R lambda_(K_alpha))`
`= (4)/(3 xx (1.097 xx 10^(7)) xx (0.76 xx 10^(-10)))`
or `(Z - 1)^(2) = 1600`
or `Z - 1 = 40`
or `Z = 41`