Find the mass of photon in motion.
The Attempt at a Solution
I just started studying modern physics and am aware of the above two equations. However equating E to 1/2mv^2 gives a different (wrong) answer while equating p to mv gives the correct expression when we consider v=c; is it wrong to write E=1/2 mv^2 or p=mv for a photon (something to do with relativity perhaps)?
I'd appreciate some insights, thank you