Question

A neutron moving with speed \(v\) makes a head-on collision with a hydrogen atom in the ground state kept at rest. The minimum kinetic energy of the neutron for which inelastic collision takes place is:

• A. \(10.2\,\text{eV}\)
• B. \(20.4\,\text{eV}\)
• C. \(12.1\,\text{eV}\)
• D. \(16.8\,\text{eV}\)

Hint:

For equal mass collisions: Maximum energy transfer = 50%.

Answer 1

The Correct Option is B

Step 1: Minimum excitation energy of hydrogen: \[ E=10.2\,\text{eV} \]
Step 2: For head-on collision with equal masses, maximum energy transfer is half.
Step 3: Hence neutron must have: \[ K_{\min}=2\times10.2=20.4\,\text{eV} \]