I never understood why light has momentum but no mass.. until now!

Light (or photons) is massless. Yet, photons have momentum given by the equation P = E/c. Where E is the energy the photon enegy and c is the speed of light. The goal of this video is to gain a deep intuition behind it. First to understand where the light's momentum really comes from. Second, to use that intuition to derive the equation without using anything quantum. But, by connecting all the fundamental equations of high school electromagnetism. I first learnt about this from Feynman lectures. You can find his actual derivation in the last paragraph of his Volume 2, chapter 34 - "Relativistic effects in radiation". https://www.feynmanlectures.caltech.edu/I_34.html#:~:text=We%20now%20appreciate%20that%20light,%CF%89%2Cp%3D%E2%84%8Fk.