A : The radiation pressure due to light waves is maximum when the surface is a perfect reflector.
R : The momentum transfer by the photons to a perfectly reflecting surface is maximum.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1)
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2)
C. If assertion is true statement but Reason is false, then mark (3)
D. If both Assertion and Reason are false statements, then mark (4)

Answer

To solve the assertion-reason question, we will analyze both the assertion (A) and the reason (R) step by step.

### Step 1: Understand the Assertion (A)
The assertion states: "The radiation pressure due to light waves is maximum when the surface is a perfect reflector."

- **Explanation**: Radiation pressure is defined as the force exerted by light waves per unit area on a surface. When light waves strike a surface, they impart momentum to that surface. For a perfect reflector, the light does not get absorbed; instead, it reflects back with the same momentum. This results in a greater change in momentum, which leads to higher radiation pressure.

### Step 2: Understand the Reason (R)
The reason states: "The momentum transfer by the photons to a perfectly reflecting surface is maximum."

- **Explanation**: When photons strike a perfectly reflecting surface, they reverse direction without losing any energy. The momentum of a photon is given by \( p = \frac{E}{c} \), where \( E \) is the energy of the photon and \( c \) is the speed of light. For a perfectly reflecting surface, the change in momentum for each photon is twice its initial momentum (since it goes from \( p \) to \( -p \)). This means that the total momentum transferred to the surface is maximized, resulting in maximum radiation pressure.

### Step 3: Conclusion
Since both the assertion and the reason are true, and the reason correctly explains the assertion, we conclude that:

- **Final Answer**: Both assertion and reason are true, and the reason is the correct explanation of the assertion.