List of top Physics Questions on Half life asked in MHT CET

Activity of a radioactive sample decreases to $\left(\dfrac{1}{4}\right)^{th}$ of its original value in 4 days. Then in 16 days its activity will become $x$ times the original value. The value of $x$ is

A radioactive sample has half-life of \(5\) years. The percentage of fraction decayed in \(10\) years will be

Two samples A and B contain equal amount of radioactive substances. If \((\frac{1}{8})^{th}\) of sample A and \((\frac{1}{128})^{th}\) of sample B, remain after 9 hours, then the ratio of half life period of B to that of A is

The half-life of the isotope \(_{11}\text{Na}^{24}\) is 15 hr. How much time does it take for \((\frac{7}{8})^{\text{th}}\) of a sample of this isotope to decay ?