The X-ray wavelength of `L_(alpha)` line of platinum `(Z=78)` is `1.30Å`. The X-ray wavelength of `L_(alpha)` line of molybdenum `(Z=42)` is

Options

A. `5.41 Å`
B. `4.20 Å`
C. `2.70 Å`
D. `1.35 Å`

Answer

A

Explanation

`lamda` for `k_alpha` line
`q/lamda=r(Z-7.4)^2(1/2^2-1/3^2)`
`lamdaprop1/((Z-7.4)^2),lamda_1/lamda_2 =((Z_2-7.4)/(Z_1-7.4))^(2)implies lamda_2=5.41Å`