A y-ray photon is emitted

Options

A. (a) after ionization of an atom
B. (b) due to conversion of a neutron nto a neutorn in the nucleus
C. (c) after de-excitation of a nucleus
D. (d) due to conversion of a proton into a neutron in the nucleus

Answer

### Step-by-Step Solution:

1. **Understanding the Context**: The question involves the emission of a gamma ray photon, which is a form of electromagnetic radiation. It is important to understand the conditions under which gamma rays are emitted from an atom.

2. **Identify the Processes**: Gamma ray photons can be emitted during various nuclear processes, including:
- Ionization of an atom
- Conversion of a neutron into a proton
- De-excitation of a nucleus
- Conversion of a proton into a neutron

3. **Focus on De-excitation**: Among the processes listed, gamma ray emission is primarily associated with the de-excitation of a nucleus. This occurs when a nucleus transitions from a higher energy state to a lower energy state, releasing energy in the form of gamma radiation.

4. **Energy Consideration**: When an atom undergoes alpha or beta decay, it may still have excess energy. The emission of a gamma ray photon helps to release this excess energy, leading to a more stable nuclear configuration.

5. **Conclusion**: The correct answer to the question is that a gamma ray photon is emitted due to the de-excitation of the nucleus. This process occurs when the nucleus transitions from an excited state to a more stable state, resulting in the release of gamma radiation.

### Final Answer:
A gamma ray photon is emitted due to the de-excitation of the nucleus.

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