$A$ radioactive sample has a half-life of $5$ years. The probability of decay in $10$ years will be ........$\%$

For a radioactive material,the half-life is $10$ minutes. If initially there are $600$ nuclei,the time taken (in minutes) for the disintegration of $450$ nuclei is:

The half-life of a radioactive element is $20 \, minutes$. What is the time interval (in $minutes$) between $33\%$ decay and $67\%$ decay?

The half-life of a radioactive element is $10 \ h$. The fraction of initial radioactivity of the element that will remain after $40 \ h$ is

$A$ and $B$ are two radioactive elements. Their half-lives are $1 \, year$ and $2 \, years$ respectively. Initially,$10 \, g$ of $A$ and $1 \, g$ of $B$ are taken. After how many years will their remaining quantities be equal?

The activities of three radioactive substances $A, B$ and $C$ are represented by the curves $A, B$ and $C$ in the figure. Then their half-lives $T_{\frac{1}{2}}(A) : T_{\frac{1}{2}}(B) : T_{\frac{1}{2}}(C)$ are in the ratio: