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 nulceus 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 statement is not correct about Bohr's model of the hydrogen atom, we need to review the key postulates of the model.

### Step-by-Step Solution:

1. **Understand the Postulates of Bohr's Model:**
- Bohr proposed that electrons revolve around the nucleus in certain stable orbits without emitting energy.
- Each orbit has a specific energy level, and electrons can only exist in these orbits.
- The angular momentum of the electron in these orbits is quantized and is given by the formula: \( L = n \frac{h}{2\pi} \), where \( n \) is a positive integer (1, 2, 3,...), and \( h \) is Planck's constant.
- When an electron transitions between orbits, it emits or absorbs a photon whose energy corresponds to the difference in energy between the two orbits.

2. **Evaluate the Statements:**
- **Statement 1:** Electrons revolve in stable orbits without emitting energy. (Correct)
- **Statement 2:** Electrons can only occupy certain stable orbits. (Correct)
- **Statement 3:** The angular momentum of the electron is quantized. (Correct)
- **Statement 4:** An electron can revolve in any orbit. (Incorrect)

3. **Identify the Incorrect Statement:**
- From the evaluation, Statement 4 is not correct according to Bohr's model. Bohr's model states that electrons can only occupy certain stable orbits, not any arbitrary orbit.

### Conclusion:
The statement that is not correct about Bohr's model of the hydrogen atom is that "an electron can revolve in any orbit."