Question

The half life of a radioactive element is $140$ days. After $560$ days, $1gm$ of the element will be reduced to:

• A. $1/2gm$
• B. $1/4gm$
• C. $1/8gm$
• D. $1/16gm$

Answer 1

Answer: (D)

$1/16gm$

$t_{1/2}=140days$

After $4t_{1/2},1gm$ of element reduces to $(\frac{1}{2}{)}^4\times 1=\frac{1}{16}gm$