Question

Assertion: EM radiation when falls on a surface exerts pressure. Reason: Radiation has no rest mass.

• A. A and R both are correct and R is correct explanation of A
• B. A and R both are correct but R is not correct explanation of A
• C. A is correct but R is incorrect
• D. A is incorrect but R is correct

Hint:

Momentum of a photon: \[ p = \frac{E}{c} \] Radiation pressure arises due to momentum transfer of photons.

Answer 1

The Correct Option is B

Concept: Electromagnetic radiation carries momentum even though photons have no rest mass. When radiation strikes a surface, momentum transfer occurs which produces radiation pressure.
Step 1: Analyze the Assertion. Electromagnetic radiation exerts pressure on a surface because photons carry momentum. Thus, the assertion is correct.
Step 2: Analyze the Reason. Radiation indeed has no rest mass, which is also correct. However, radiation pressure occurs because photons possess momentum, not because they lack rest mass. Thus, \[ \boxed{\text{Both A and R are correct, but R is not the correct explanation of A}} \]