Answer:
[tex]\lambda = 1.45*10^{-10} m[/tex]
Explanation:
wavelength of K_a X ray can be computed by using following relation
[tex]\frac{1}{\lambda} = R(Z-1)^2 [\frac{1}{n_1^2 - \frac{1}{n^2_2}}][/tex]
for K_a ray, [tex]n_1 = 1, n_2 = 2[/tex]
therefore
[tex]\frac{1}{\lambda} = R(30-1)^2 [\frac{1}{1} - \frac{1}{4}][/tex]
[tex]\frac{1}{\lambda} = \frac{R*841*3}{4}[/tex]
[tex]\lambda = \frac{4}{R*841*3}[/tex]
Where R is Rydberg constant = 1.097 *10^7 m^{-1}
[tex]\lambda = \frac{4}{1.097 *10^7*841*3}[/tex]
[tex]\lambda = 1.45*10^{-10} m[/tex]
