How does light have energy? How can light exert force?

Question

Here is what I know:

Photons have no mass.

Force is change in momentum over change in time.

Momentum is mass times velocity.

E=mc²

SO HOW DOES LIGHT HAVE ENERGY AAAA

I also read that massless particles can have momentum and I do not understand that at all.

Please explain how all of this is connected and how light has energy and exerts force. Thank you!

In: 9

Answer 1

Photons have relativistic mass, so it satisfies E=mc^2. All of that mass is attributed to the kinetic energy. What you are looking for is rest mass, if a particle didn’t move. And it’s correct that a photon would have in fact, no mass at standstill.