JEE Mains · Physics · STD 12 - Electromagnetic waves
- JEE Mains 2026
- Medium
- MCQ
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): The electromagnetic wave exerts pressure on the surface on which they are allowed to fall.
Reason (R): There is no mass associated with the electromagnetic waves.
In the light of the above statements, choose the correct answer from the options given below :
Pick an option to check your answer.
Answer & Solution
Correct Answer
(B) Both (A) and (R) are true but (R) is not the correct explanation of (A)
Step-by-step Solution
Detailed explanation
Assertion (A) is true because electromagnetic waves carry energy and momentum. When they strike a surface, they transfer momentum to it, which results in a force and consequently exerts radiation pressure on the surface.
Reason (R) is true because electromagnetic waves consist of photons, which have zero rest mass. Thus, there is no rest mass associated with electromagnetic waves.
However, the pressure exerted by electromagnetic waves is due to the momentum they carry (\(p = \dfrac{E}{c}\)), not because they are massless. Therefore, both (A) and (R) are true, but (R) is not the correct explanation of (A).
Answer: Both (A) and (R) are true but (R) is not the correct explanation of (A)
Reason (R) is true because electromagnetic waves consist of photons, which have zero rest mass. Thus, there is no rest mass associated with electromagnetic waves.
However, the pressure exerted by electromagnetic waves is due to the momentum they carry (\(p = \dfrac{E}{c}\)), not because they are massless. Therefore, both (A) and (R) are true, but (R) is not the correct explanation of (A).
Answer: Both (A) and (R) are true but (R) is not the correct explanation of (A)
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