Half lives for `alpha` and `beta` emission of a radioacative materila are 16 years and 48 years respectively. When material decays giving `alpha` and `beta` emission simultaneously, time in which `3//4^(th)` material decays is .

Options

A. 29 years
B. 24 years
C. 64 years
D. 12 years

Answer

B

Explanation

Effective half life is calculated as
`(1)/(T) = (1)/(T_(1)) +(1)/(T_(2))`
`(1)/(T) = (1)/(16) +(1)/(48) rArr T = 12 ` years
Time in which `(3)/(4)` will decay is 2 half lives = 24 years.