The half-life of a radioactive substance is $120$ days. After $480$ days,the amount of $4 \ g$ of the substance remaining will be: (in $g$)

The average life period of a radioactive element is the reciprocal of its

The number of $\alpha$-particles emitted per second by a radioactive element falls to $1/32$ of its original value in $50 \ days$. The half-life period of this element is .......... $days$.

$87.5\%$ decomposition of a radioactive substance completes in $3$ hours. What is the half-life of that substance?

$A$ radioactive isotope having a half-life of $3 \ days$ was received after $12 \ days$. It was found that there were $3 \ g$ of the isotope in the container. The initial weight of the isotope when packed was ......... $g$.

The half-life period for a radioactive substance is $15$ minutes. How many grams of this radioactive substance is decayed from $50$ g of substance after $1$ hour?