The electrons in a `H`- atom kept at rest , jumps from the mth shell to the nth shell `(m gt n)`. Suppose instead of emitting electromagnetic wave, the energy released is converted into kinetic energy of the atom. Assuming Bohr's model and conservation of angular momentum are valid. Now , answer the following questions:
If the above comprehension be true , ehat is not valid here?

Options

A. `F = ma`
B. `tau = 1 alpha`
C. `F = dp//dt`
D. All of them

Explanation

To solve the question, we need to analyze the scenario described and identify what is not valid based on the principles of atomic physics, specifically under the assumptions of Bohr's model and conservation of angular momentum.

### Step-by-Step Solution:

1. **Understanding the Transition**:
- In a hydrogen atom, when an electron transitions from a higher energy level (m-th shell) to a lower energy level (n-th shell), it typically emits energy in the form of a photon. This energy corresponds to the difference in energy between the two shells.

2. **Energy Conservation**:
- The energy released during this transition is given by the formula:
\[ E = E_m - E_n \]
- Where \(E_m\) and \(E_n\) are the energies of the m-th and n-th shells respectively.

3. **Kinetic Energy Conversion**:
- The problem states that instead of emitting a photon, this energy is converted into kinetic energy of the atom. This is a crucial point because it implies that the atom itself gains kinetic energy, which is not the typical behavior expected in atomic transitions.

4. **Angular Momentum Conservation**:
- According to Bohr's model, the angular momentum of an electron in a stable orbit is quantized and given by:
\[ L = n \frac{h}{2\pi} \]
- If the electron transitions from the m-th shell to the n-th shell, the angular momentum should change accordingly. However, if we assume that the atom gains kinetic energy, this implies a change in the system's overall momentum.

5. **Identifying What is Not Valid**:
- The assumption that the energy released can be converted into kinetic energy of the atom without emitting a photon contradicts the conservation of momentum. If the atom gains kinetic energy, it must also emit a photon to conserve momentum, which is not accounted for in this scenario.
- Additionally, if the electron does not emit a photon, it suggests that the transition does not involve any change in the electromagnetic field, which is inconsistent with the principles of quantum mechanics.

6. **Conclusion**:
- Therefore, the statement that the energy released during the transition can be converted into kinetic energy of the atom without violating conservation laws is not valid. The correct understanding is that the energy must be released as a photon, ensuring that both energy and momentum conservation principles are upheld.

### Final Answer:
The assumption that the energy released during the electron's transition can be converted into kinetic energy of the atom without emitting a photon is not valid.