Assertion: A photon has no rest mass, yet it carries definite momentum. Reason: Momemtum of photon is due to its energy and hence its equivalent mass.

Question

Assertion: A photon has no rest mass, yet it carries definite momentum. Reason: Momemtum of photon is due to its energy and hence its equivalent mass. (A) If both assertion and reason are true and reason is the correct explanation of assertion (B) If both assertion and reason are true but reason is not the correct explanation of assertion (C) If assertion is true but reason is false (D) If both assertion and reason are false

Tardigrade Admin · Accepted Answer

Equivalent mass of photon (m) is given from equation

E = m c^{2} = h υ

∴ m = \frac{h υ}{c ^{2}}

Where

E

is energy,

m

is mass,

c

is speed of light,

h

is Planck’s constant,

u

is frequency.

∴

Momentum of photon

= \frac{h υ}{c ^{2}} \times c = \frac{h υ}{c}

Q. Assertion: A photon has no rest mass, yet it carries definite momentum. Reason: Momemtum of photon is due to its energy and hence its equivalent mass.

If both assertion and reason are true and reason is the correct explanation of assertion

If both assertion and reason are true but reason is not the correct explanation of assertion

If assertion is true but reason is false

If both assertion and reason are false

Equivalent mass of photon (m) is given from equation E=mc2=hυ ∴m=c2hυ​ Where E is energy, m is mass, c is speed of light, h is Planck’s constant, u is frequency. ∴ Momentum of photon =c2hυ​×c=chυ​

Q. Assertion: A photon has no rest mass, yet it carries definite momentum.
Reason: Momemtum of photon is due to its energy and hence its equivalent mass.

Equivalent mass of photon (m) is given from equation
$E = m c^{2} = h υ$
$∴ m = \frac{h υ}{c ^{2}}$
Where $E$ is energy, $m$ is mass, $c$ is speed of light, $h$ is Planck’s constant, $u$ is frequency.
$∴$ Momentum of photon $= \frac{h υ}{c ^{2}} \times c = \frac{h υ}{c}$