Q108 / 180 · AIIMS 2013 · Physics
When a slow neutron is captured by a ${ }_{92}^{235} \mathrm{U}$ nucleus, a fission energy releasing $200 \mathrm{MeV}$. If power of nuclear reactor is $100 \mathrm{~W}$ then rate of nuclear fission is
- A$3.6 \times 10^6 \mathrm{~s}^{-1}$
- Correct answerB$3.1 \times 10^{12} \mathrm{~s}^{-1}$
- C$1.8 \times 10^4 \mathrm{~s}^{-1}$
- D$4.1 \times 10^6 \mathrm{~s}^{-1}$
Solution
Number of fission per second
$=\frac{\text { total power }}{\text { energy/fission }}$.
Here, total power $=100 \mathrm{~W}$
energy/fission $=200 \mathrm{MeV}=200 \times 10^6 \times 1.6 \times 10^{-19} \mathrm{~J}$
$=3.2 \times 10^{-11} \mathrm{~J}$
$\therefore \quad$ fission rate $=\frac{100}{3.2 \times 10^{-11}}=3.1 \times 10^{12} \mathrm{~s}^{-1}$
Hence, the correct answer is option: 'B'.