Question

The wavelength of `L_alpha` line in X-ray spectrum of `._76Pt` is 1.32Å. The wavelength of `L_alpha` line in X-ray spectrum of another unknown element is 4.17Å. If screening constant for `L_alpha` line is 7.4, then atomic number of the unknown element is
A. 78
B. 47
C. 40
D. 35

Answer 1

Correct Answer - B
`sqrt(v) =a(Z-b)=sqrt(C/(lambda)) =a(Z-b)rArr sqrt((lambda_(2))/(lambda_(1)))=(a(78-7.4))/(a(Z_(2)-7.4))`
`Z_(2)=47`