The half life period of a radioactive substance is 10 hours. How much will be left after 4 hours in 1g atom sample ?

Options

A. `45.6 xx 10^(23)` atoms
B. `4.56 xx 10^(23)` atoms
C. `4.56 xx 10^(24)` atoms
D. `4.56 xx 10^(25)` atoms

Answer

B

Explanation

`N_(t) = N_(0) ((1)/(2))^(n) n = 4//10`
`:. N_(t) = 6.022 xx 10^(23) xx ((1)/(2))^(-.4) = 4.56 xx 10^(23)`