Which of the following is not correct about bohr model of the hydrogen atom ?

Options

A. 1. An electron in an atom could revolve in certain stable orbits without the emission of radiant energy.
B. 2. Electron revolves around the nucleus only in those orbits for which angular momentum `L_n=(nh)/(2pi)`.
C. 3. when electron make a transition from one of its stable orbit to lower orbit then a photon emitted with energy `hupsilon=E_f-E_i`.
D. 4. Bohr model is applicable to all atoms.

Explanation

To determine which of the statements about the Bohr model of the hydrogen atom is not correct, we need to analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding the Bohr Model**:
The Bohr model describes the behavior of electrons in an atom, particularly hydrogen. It suggests that electrons move in fixed orbits around the nucleus and that these orbits have quantized energy levels.

2. **Analyzing Each Option**:
- **Option 1**: "An electron in atom could revolve in certain stable orbit without the emission of a radiant energy."
- This statement is correct. According to the Bohr model, electrons in stable orbits do not emit energy.

- **Option 2**: "Electron revolves around the nucleus only in those orbits for which angular momentum L is equal to n(h/2π)."
- This statement is also correct. Bohr postulated that the angular momentum of the electron is quantized and is an integer multiple of h/2π.

- **Option 3**: "When an electron makes a transition from one of its stable orbits to a lower orbit, then a photon emits energy with energy hν = E_f - E_i."
- This statement is correct. The energy difference between the orbits corresponds to the energy of the emitted photon when an electron transitions between levels.

- **Option 4**: "Bohr model is applicable to all atoms."
- This statement is not correct. The Bohr model is primarily applicable to hydrogen-like atoms (single electron systems) and does not accurately describe multi-electron atoms due to electron-electron interactions and other complexities.

3. **Conclusion**:
The statement that is not correct about the Bohr model of the hydrogen atom is **Option 4**: "Bohr model is applicable to all atoms."

### Final Answer:
**The statement that is not correct about the Bohr model of the hydrogen atom is: "Bohr model is applicable to all atoms."**