Hydrogen atom travelling with a certain speed v colliding with a photon of wavelength 200 nm travelling in opposite direction and stops . Assume that entire energy of photon is absorbed by the hydrogen atom and calculate v.

Explanation

To solve the problem of a hydrogen atom colliding with a photon and stopping, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Given Data:**
- Wavelength of the photon, \( \lambda = 200 \, \text{nm} = 200 \times 10^{-9} \, \text{m} \)
- Mass of the hydrogen atom, \( m_h = 1.67 \times 10^{-27} \, \text{kg} \)
- Planck's constant, \( h = 6.63 \times 10^{-34} \, \text{Js} \)
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