Question

So in my textbook, it states that the E=hf equation applies to electrons, and all particles, not just photons.

But in order to prove this, wouldn't these particles need to have zero mass, to satisfy E=pc from Einstein's equation? In Einstein's theory of relativity E²=p²c²+m²c⁴, we get E=pc because we consider the mass to be zero.

For E=hf to work for other particles, don't we need to assume electrons have zero rest mass?

Answer 1

The equation E=hf applies to electrons and all particles, not just photons. For particles with mass, the equation E²=(pc)²+(mc²)² is used. Electrons, which have a non-zero rest mass, can also be described by the equation E=hf.

Step-by-step explanation:

According to Einstein's theory of relativity, the equation E = pc applies to particles with zero rest mass, such as photons. For particles with mass, we use the equation E² = (pc)² + (mc²)².

This equation accounts for both the momentum and the rest mass of the particles.

Electrons, which have a non-zero rest mass, can also be described by the equation E = hf, where h is Planck's constant and f is the frequency of the particle. This equation applies to all particles, not just photons, but it is important to consider the appropriate equations depending on the properties of the particle being analyzed.