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Light has no mass so it also has no energy according to Einstein, but how can sunlight warm the earth without energy?


Grag 16th Nov, 2021
Answer (1)
Nitin Mereddy 16th Nov, 2021

In the above equation, E is the total energy of the particle, p is the momentum of the particle (which is related to its motion), c is the speed of light, and m is the mass of the particle. This equation can be derived from the relativistic definitions of the energy and momentum of a particle. The above equation tells us that the total energy of a particle is a combination of its mass energy and its momentum energy (which is not necessarily related to its mass). When a particle is at rest (p = 0), this general equation reduces down to the familiar E = mc2. In contrast, for a particle with no mass (m = 0), the general equation reduces down to E = pc. Since photons (particles of light) have no mass, they must obey E = pc and therefore get all of their energy from their momentum.

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