The ratio of radii of nuclei `._13 A1^27` and `._52 X^A` is `3 : 5`. The number of neutrons in the nuclei of `X` will be

Options

A. 52
B. 62
C. 73
D. 95

Answer

C

Explanation

The nuclear radii and mass number are related as `R prop A^(1//3)`
`therefore (R_1/R_2) = (A_1/A_2)^(1//3) therefore 5/3 = ((A_1)/(27))^(1//3)`
`therefore 125/27 = (A_1)/(27) therefore A_1 = 125 " or " A = 125`
`therefore` For X,Z = no. of protons = 52
`therefore` number of neutrons = 125 - 52 = 73