Kumar Mittal Solutions for Exercise 1: QUESTIONS

The half-life of strontium-$90$ is $30$ years. In what time (in years) will $0.04 \mathrm{g}$ strontium-$90$ become $0.005 \mathrm{g}$ after decay?

After a certain lapse of time, the fraction of radioactive polonium undecayed is found to be $3.125\%$ of its initial quantity. What is the duration of this time-lapse (in days) if the half-life of polonium is $138$ days?

$80 \mathrm{g}$ of a radioactive material is allowed to decay for $15$ days. The mass left undecayed after this period is $2.5 \mathrm{g}$. Calculate the half-life (in days) of the material.

$75\%$ of a radioactive element disintegrates in $24$ years. Calculate the half-life (in years) of the element.

The decay constant of a radioactive material is $0.002{\text{ year }}^{-1}$. Find its average life in years.

The half-life of a radioactive substance is $3$ second. Initially, it has $8000$ atoms. Find time (in seconds) after which $1000$ atoms will remain undecayed.

The half-life of a radioactive material is $24.1$ days. How long (in days) will a sample take to decay $90\%$ of it? $\left({\log }_e 2=0.6931, {\log }_e 10=2.3\right)$

At a certain instant, a piece of radioactive material contains ${10}^{12}$ atoms. The half-life of the material is $30$ days. What time (in days) would elapse before ${10}^4$ atoms remain? $({\log }_{e}10=2.31)$