Question

The half life period of radio active element is $120$ days. After $480$ days, $4gms$ of the element will be reduced to:

• A. $0.25gm$
• B. $2.0gm$
• C. $1.0gm$
• D. $0.5gm$

Answer 1

The correct option is A $0.25gm$

$t_{1/2}=120days$

After 4 half times, it is reduced to:

$=(\frac{1}{2}{)}^4\times 4gm$

$=\frac{1}{4}gm$