Which of the follwing statements about photon is incorrect ?

Options

A. Photons exert no pressure.
B. Momentum of photon is `(hv)/(c )` .
C. Rest mass of photon is zero.
D. Energy of photon is hv.

Explanation

To determine which statement about photons is incorrect, we can analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding Photons**: Photons are elementary particles that are the quantum of electromagnetic radiation, including light. They have specific properties that can be analyzed.

2. **Analyzing the Statements**:
- **Statement 1**: "Photon exerts no pressure."
- This statement is incorrect. Photons do exert pressure when they strike a surface, due to their momentum. The pressure exerted by light is a well-known phenomenon and is observed in applications like solar sails.

- **Statement 2**: "The momentum of Photon is h nu."
- This statement is incorrect. The correct expression for the momentum (P) of a photon is given by \( P = \frac{h \nu}{c} \), where \( c \) is the speed of light. Hence, this statement is not correct.

- **Statement 3**: "The rest mass of Photon is zero."
- This statement is correct. Photons are massless particles, and their rest mass is indeed zero.

- **Statement 4**: "The energy of Photon is h nu."
- This statement is correct. The energy (E) of a photon is given by the equation \( E = h \nu \), where \( h \) is Planck's constant and \( \nu \) is the frequency of the photon.

3. **Conclusion**:
- The incorrect statement about photons is **Statement 1**: "Photon exerts no pressure."

### Summary:
- The first statement is incorrect because photons do exert pressure.
- The second statement is also incorrect as the momentum of a photon is given by \( \frac{h \nu}{c} \).
- The third and fourth statements are correct regarding the rest mass and energy of photons.