Q. A neutron having mass of $1.67 \times 10^{- 27}\ kg$ and moving at $10^{8}m/s$ collides with a deutron at rest and sticks to it. If the mass of the deutron is $3.34 \times 10^{- 27}\ kg$ then the speed of the combination is
A) $2.56 \times 10^{3}\ m/s$
B) $2.98 \times 10^{5}\ m/s$
C) $3.33 \times 10^{7}\ m/s$
D) $5.01 \times 10^{9}\ m/s$
Explanation
(c) According to law of conservation of momentum
Momentum of neutron = Momentum of combination
$\Rightarrow 1.67 \times 10^{- 27} \times 10^{8} = \left( 1.67\ \times 10^{- 27} + 3.34 \times 10^{- 27} \right)v$
$\therefore v = 3.33 \times 10^{7}\ m/s$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.