Question

I have a question that is not related any of my school stuff or boards so you can answer however you like.
If light has no mass, why does it have momentum if p=mv.
Also light is said to have energy then why does it not have mass if we use

Einstein's mass-energy equivalence formula e=mc^2

I'm just asking this for my interest in physics. I'm also using 50 points so you will get a lot of points so don't hesitate in giving long answer please​

Answer 1

The answer is then definitely "no": the photon is a massless particle. According to theory it has energy and momentum but no mass, and this is confirmed by experiment to within strict limits. ... They also say that a photon has momentum, and momentum p is related to mass m by p = mv.

Answer 2

Light doesn't not have rest mass (mass when it's not travelling ) but when its travelling its mass is undefined(relativistic mass) .