JEE Main 2026 · 5 Apr · Shift 2 · Physics Q39

PhysicsSingle correct+4 / -1Question 39 of 75

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 :

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 and worked solution

Official answer: B

Assertion. EM waves carry momentum, so they exert radiation pressure. True.

Reason. EM waves have no rest mass. True.

Explanation? The pressure comes from the momentum the wave carries ( $p=E/c$ ), not from having no mass. So R does not explain A.

(B)

Topics:Energy and momentum of EM waves

JEE Main 2026 · 5 Apr · Shift 2, Physics question 39