1
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). In the light of the above statements, choose the correct answer from the options given below :
- Both (A) and (R) are true and (R) is the correct explanation of (A)
- Both (A) and (R) are true but (R) is not the correct explanation of (A)
- (A) is true but (R) is false
- (A) is false but (R) is true
Answer
(2) Both (A) and (R) are true but (R) is not the correct explanation of (A)
Solution
An EM wave carrying energy U also carries momentum p= Uc.
When it falls on a surface, this momentum is transferred a force, i.e. radiation pressure (P= Ic for full absorption). (A) is true.
EM waves (photons) have zero rest mass (R) is true.
The pressure arises from the momentum carried by the wave, not from the absence of mass (R) does not explain (A).
Answer: (2)
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