Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Search any question & find its solution
Question: Answered & Verified by Expert
A radioactive substance emits 100 beta particles in the first $2 \mathrm{~s}$ and 50 beta particles in the next $2 \mathrm{~s}$. The mean life of the sample is
PhysicsNuclear PhysicsKCETKCET 2013
Options:
  • A $4 \mathrm{~s}$
  • B $2 \mathrm{~s}$
  • C $\frac{2}{0.693} \mathrm{~s}$
  • D $2 \times 0.693 \mathrm{~s}$
Solution:
2006 Upvotes Verified Answer
The correct answer is: $\frac{2}{0.693} \mathrm{~s}$
Given, In 1st two seconds $100 \beta$ particles and in next two seconds $50 \beta$ particles are emitted
$\begin{array}{ll}
\therefore & T_{1 / 2}=2 \mathrm{~s} \\
\text { Hence, } & T_{m}=\frac{T_{1 / 2}}{0.693}=\frac{2}{0.693}
\end{array}$

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.