Question

A neutron mass $1.67\times {10}^{-27}kg$ moving with a velocity $1.2\times {10}^{7}m{s}^{-1}$ collides head-on with a deuteron of mass $3.34\times {10}^{-27}kg$ initially at rest. If the collision is perfectly elastic,, what would be speed of deuteron after the collision?

• A.
• B.
• C.
• D.

Answer 1

The correct option is D

In an elastic collision, both momentum and energy are conserved. Using the two laws, it is easy to see that $(\because M=2m)$, the deuteron will move forward with a speed $\frac{2v}{3}=\frac{2\times 1.2\times {10}^7}{3}=0.8\times {10}^{7}m{s}^{-1}$. Hence the correct chioce is (d).