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Given below are two statements : one is labelled as Assertion (A) and other is labelled as Reason (R). Assertion (A) : Electromagnetic waves carry energy but not momentum. Reason (R) : Mass of a photon is zero. In the light of the above statements, choose the most appropriate answer from the options given below :

1. (1) (A) is true but (R) is false.
2. (2) (A) is false but (R) is true.
3. (3) Both (A) and (R) are true but (R) is not the correct explanation of (A).
4. (4) Both (A) and (R) are true and (R) is the correct explanation of (A).

Correct answer: (2) (A) is false but (R) is true.

Solution

The assertion is incorrect because electromagnetic waves do carry momentum, despite photons having zero mass. The reason is true as photons indeed have no mass, which is a separate fact that does not support the assertion.

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