The half-life of $^{60}Co$ is $7 \ years$. If $1 \ g$ of it decays,the amount of the substance remaining after $28 \ years$ is (in $g$)

The ratio of $\frac{{}^{14}C}{{}^{12}C}$ in a piece of wood is $\frac{1}{8}$ part that of the atmosphere. If the half-life of ${}^{14}C$ is $5730 \text{ years}$,the age of the wood sample is $.....$ years.

What is the order of radioactive decay of a substance?

The half-life of $1 \ g$ of a radioactive sample is $9 \ hours$. The radioactive decay obeys first-order kinetics. The time required for the original sample to reduce to $0.2 \ g$ is .......... $hours$.

The half-life of a radioactive isotope is $3 \ hr$. The value of its disintegration constant is: (in $hr^{-1}$)

If the quantity of a radioactive element is doubled,then its rate of disintegration per unit time will be