Chapter 38, Problem 1DQ

To determine

In what ways photons resemble other particles such as electrons and what way do they differ and whether the photons have mass and electric charge. Also determine if photons can be accelerated and their mechanical properties.

Answer to Problem 1DQ

Photons are elementary particles like electrons but are force carriers and not part of matter. Photons have zero rest mass and are charge less particles. Photons cannot be accelerated in the local frame and have momentum and energy proportional to the frequency.

Explanation of Solution

The packages of electromagnetic energy are carried by particles called photons.

Photons are elementary particle that are force carriers of electromagnetic force. Electron are fundamental particles but are not force carriers rather constituents of matter. Both electron and photon exhibit wave-particle duality and are quantum particles. Electrons are charged while photons are charge less.

Photons have zero rest mass. They move with a constant velocity given by $c$ and do not get accelerated in the local frame. Photons are charge less particles but have energy and momentum proportional to the frequency of the wave. The energy of one photon is proportional to the frequency and inversely proportional to the wavelength. The magnitude of momentum is given by $\frac{E}{c}$ where $E$ is the energy.

Conclusion:

Thus, photons are elementary particles like electrons but are force carriers and not part of matter. Photons have zero rest mass and are charge less particles. Photons cannot be accelerated in the local frame and have momentum and energy proportional to the frequency.