What is the rest mass of a photon?
Correct answer: A. Zero
- A. Zero
- B. Equal to the mass of electron
- C. Equal to the mass of proton
- D. Infinite
Explanation
Photons, being massless particles, have a rest mass of zero. According to special relativity, photons always travel at the speed of light (c) and have no rest mass. This means that a photon's energy (E) is equal to its momentum (p) multiplied by the speed of light (E = pc), and its rest mass is zero.
This question appeared on the KMU MDCAT 2023 (retake) paper, which you can sit online with every answer explained.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Photons and the Particle Model of Light
The particle model treats light as photons with energy E equals hf and momentum related to wavelength. Questions involve the photoelectric effect, work function, threshold frequency, stopping potential and photon energy, while distinguishing particle behaviour from the wave description of interference and diffraction.
Practise Dawn of Modern Physics
739 free Dawn of Modern Physics MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Photons and the Particle Model of Light questions
When photons of energy hv are incident on the surface of photosensitive material of work function hv0, then:
the momentum of a photon is written as;
Which of the following has the high energy photon?
The momentum of wave where wavelength is 1.32 x 10^-9 m:
Choose the correct relationship, when E=energy, h=plank's constant, c=velocity of light, ν =frequency, λ =wave length:
Light of wavelength 15 x 10^-7 m consists of photons whose energy is;