The ratio of the amount of two element X and Y at radioactive equilibrium is `1 : 2 xx 10^(-6)`. If the half-life period of element Y is `4.9 xx 10^(-4)` days, then the half-life period of element X will be

Options

A. `4.8 xx 10^(-3)` years
B. 245 years
C. 122.5 days
D. None of these

Answer

B

Explanation

`N_X/N_Y = (t_(1//2) (X))/(t_(1//2) (Y)) , t_(1//2) (X) = ( 4.9 xx 10^(-4))/(2xx10^(-6)) = 245` days