Question

The probability of a radioactive atom to survive 5 times longer than its half-life period is :

• A. 2/5
• B. $2\times 5$
• C. $2^{-5}$
• D. $2^5$

Answer 1

The correct option is C $2^{-5}$

As we know,
$N=N_0/2^n$ = no of remaining atoms after n half life.

So, after 5 half life, remaining atoms are $1/2^5$ times of initial.