quantum mechanics - Can the equation $E = hnu$ be used not only for light, but for radio waves? (Since they are all part of the electromagnetic spectrum)

Can the equation $E = h\nu$ (or $E = hf$) be used to find the energy of the particles from the electromagnetic spectrum? I mean, for example light is part of the EM, a radio wave is also part of the EM, can we find the energy of the particles that make up the radio waves? Light is made up of photons, and with the equation we can find their energy, well, can we find the energy of the particles that radio waves (or other parts of the EM, except the visible light) are made of? Sorry for the stupid question, I am just getting into Quantum Mechanics (Khan Academy).

Answer

Yes you can. The relation $E=h\nu$ is quite general and lies in the heart of quantum mechanics. It gives the energy of any radiation that is vibrating at a frequency of $\nu$.

Although later, we generally replace this with $E=\hbar \omega$, because $\omega$ forms a nice 4-vector with $\textbf{k}$, which is the wave number. But it also basically says the same thing since $\hbar = h/2\pi$ and $\omega=2\pi\nu$.

So, I would suggest you to get familiar with this notation. But you can use the formula you mention as long as you are not dealing with Relativity :)