Question

Assertion : A photon has no rest mass. yet it carries definite momentum. 

Reason : Momentum of photon is due to its energy and hence its equivalent mass.

(a) Both A and R are true and R is the correct explanation of A

(b) Both A and R are true but R is not correct explanation of A

(c) A is true but R is false

(d) A and R are false

Answer 1

The correct option is (a).

Explanation:

Equivalent mass of photon (m) is given from equation

E = mc² = hv

m = hv/c²

Where E is energy, m is mass, c is speed of light,h is Planck's constant, v is frequency 

.'. Momentum of Photon = hv/c² x c = hv/c