The initial mass of a radioactive element is `40g`. How many grams of it would be left after 24 years if its half`-` life period I s of 8 years ? a)2 b)5 c)10 d)20

Options

A. 2
B. 5
C. 10
D. 20

Answer

B

Explanation

`N = (N_(0))/(2^(n)) and n = (24)/(8) = 3`
`N = (40)/(2^(3)) = (40)/(8) = 5`