Question

How can we show that the light is massless by using energy-momentum equality ?

Answer 1

Light has mass doesn't i? :P

Answer 2

has it ? :S

Answer 3

yes.. photons have mass.. atleast thats what i think :P

Answer 4

so, how much ?

Answer 5

you can do mc^2 = hf
and calculate m = ?

Answer 6

this is rest mass energy formula.. you can use when amount of mass turn completely into energy.. Photon does not have rest mass.. at least we can not measure it yet..

Answer 7

photons (from what i recall) don't have mass. They move at the speed of light and as particles moving at a certain velocity approach the speed of light their masses approach zero.