Question

20. The rest mass of photon is -
(a) 1.76 x 10-35 kg
(b) zero
(C) 9 x 10-31 kg
(d) 1 a.m.u
​

Answer 1

According to Einstein's quantum theory light propagates in the form of packets i.e. quanta of energy, which is called photon.

The rest mass of photons is being zero. It can be shown, according to the relativity theory of light.

According to the relativistic theory equation, the mass of the photon is computed as:

m=

1−

c

2

v

2

m

0

m

0

=m

1−

c

2

v

2

when v=0;

So m

0

=0

Where m

0

is the rest mass of the Photon.

Answer 2

Answer:

(C) zero

Explanation:

mass of photon is zero, irrespective of if it is in rest or in motion.

If you see the meaning of 'Photon', it would say,' a massless and chargeless type of particle'. You can easily infer that mass of photon=0(MASS IS ALWAYS CONSTANT.)

Hope this helps.Thank you.