goring
Lv 6
goring asked in Science & MathematicsPhysics · 2 months ago

# how come Photons are deemed to be mass less when the equation for its energy contains mass=E= Mass x C^2?

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• 2 months ago

Ummmmmmm ...

Where did you get the idea that equation says something with energy must also have mass?

• 2 months ago

Wrong equation. E = hv where

E= energy

h = Planck constant, which really is "constant"

v = frequency, NOT velocity.

The speed of light IS NOT "CONSTANT"!!!!!

• Andrew Smith
Lv 7
1 month agoReport

goring, your perfect square wave has an infinite acceleration unless the amplitude of your infinite frequency is zero.  So does a wave of infinite frequency with zero amplitude represent a real wave?  But what has that to do with the question?

• 2 months ago

E = mc^2 only applies to an object at rest. Photons are never at rest. The full equation is

E^2 = (mc^2)^2 + (pc)^2

The energy of a photon is also given by  E = hf where f is its frequency and h is planks constant.

• Anonymous
2 months ago

E= Mass x C^2 is only for stationary objects.

In general

E^2 = (Mass x C^2)2 + (Momentum x C)^2