If ${N_0}$ is the original mass of the substance of half life period ${T_{1/2}} = 5$ years, then the amount of substance left after $15$ years is
${N_0}/8$
${N_0}/16$
${N_0}/2$
${N_0}/4$
The half life of a radioactive isotope $X$ is $50$ years. It decays to another element $Y$ which is stable. The two elements $X$ and $Y$ were found to be in the ratio of $1 : 15$ in a sample of a given rock. The age of the rock was estimated to be..........$years$
The half-life of a radioactive nuclide is $100 \,hours.$ The fraction of original activity that will remain after $150\, hours$ would be :
The average life $T$ and the decay constant $\lambda $ of a radioactive nucleus are related as
For a radioactive material, half-life is $10$ minutes. If initially there are $600$ number of nuclei, the time taken (in minutes) for the disintegration of $450$ nuclei is
Which of the following is not a mode of radioactive decay