consider an elastic collision between a neutron and a light particle like carbon and calculate fractional KE lost.

Explanation

To solve the problem of calculating the fractional kinetic energy lost during an elastic collision between a neutron and a light particle like carbon, we can follow these steps:

### Step 1: Define the masses and initial conditions
Let:
- Mass of neutron, \( m_1 = m \) (for simplicity, we can take \( m_1 = 1 \) unit)
- Mass of carbon, \( m_2 = 12 \) units (as carbon has an atomic mass of approximately 12)
- Initial velocity of neutron, \( u \)
- Initial velocity of carbon, \( u_2 = 0 \) (since it is at rest)
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