How do photons have energy if they are massless particles?

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According to Einstein E²=(mc²)²+(pc)². In the case of photons m would be equal to zero since photons are massless, so the equation simplifies to E²=(pc)². p represents momentum but because p=mv and mass is still zero, p would also be zero. Therefore E should also be equal to zero, but this doesn’t make sense since light must have energy (eg. solar energy). I hope I’ve explained my thoughts clearly and thanks to anyone who can help me understand.

In: Physics

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Anonymous 0 Comments

p = mv is the nonrelativistic limit (v/c ≈ 0). Light obviously has to be treated relativistically, as light travels at… well… the speed of light.

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