List of top Physics Questions on deccay rate asked in JEE Advanced

Half-life of a radioactive substance A is 4 days. The probability that a nucleus will decay in two half-lives is

After 280 days, the activity of a radioactive sample is 6000 dps. The activity reduces to 3000 dps after another 140 days. The initial activity of the sample in dps is

Two radioactive materials $X_1$ and $X_2$ have decay constants $10\lambda$ and $\lambda$ respectively. If initially they have the same number of nuclei, then the ratio of the number of nuclei of $X_1$ to that of $X_2$ will be 1/e after a time

During a negative beta decay