9
votes
3answers
2k views

Explain how (or if) a box full of photons would weigh more due to massless photons

I understand that mass-energy equivalence is often misinterpreted as saying that mass can be converted into energy and vice versa. The reality is that energy is always manifested as mass in some ...
5
votes
5answers
882 views

Does a photon instantaneously gain $c$ speed when emitted from an electron?

An excited electron looses energy in the form of radiations. The radiation constitutes photons which move at a speed $c$. But, is the process of conversion of the energy of the electron into the ...
2
votes
4answers
4k views

Does light accelerate or slow down during reflection?

After all, it does change direction when reflection occurs. So shouldn't it also accelerate? And since the acceleration cannot increase the speed of light, mustn't it slow down?
3
votes
3answers
4k views

Mass of particle near light speed in a medium

I am trying to get a common understanding from these two previous questions: Why does the mass of an object increase when its speed approaches that of light? What happens if light/particles exceeded ...
1
vote
4answers
2k views

Where do photons get their energy from?

If energy required to accelerate a particle to the speed of light is infinite then where do they get it from? But first if photon's are massless, then why do they collide to some other thing and get ...
2
votes
3answers
913 views

What starts the movement of a photon

Although a photon has no (rest) mass, it does have a measurable speed. Its movement can be altered by gravity. A photon "travels". If I turn on a flashlight, seen by someone at a distance, the photons ...
1
vote
1answer
1k views

If photons are deflected by a strong gravitational field, then how come photons do not have mass? [duplicate]

Possible Duplicate: Explain how (or if) a box full of photons would weigh more due to massless photons It has been proved and showed through experiments that light can be bent by the Sun or ...
3
votes
1answer
659 views

Why does light not slow down?

Clearly light bounces off of things, going really really fast. I'm curious to understand how light interacts with matter in order to bounce without: Applying force to the object Losing speed So my ...
6
votes
2answers
158 views

At Interfaces Does Light Have to Accelerate?

First, I'm not sure if photons have to "get up to" the speed of light, or if they are thrown into existence at that speed. I know that they should just be generated moving at their speed, and I know ...
1
vote
1answer
147 views

Do Photons Accelerate Upon Creation? [duplicate]

Of course the speed of light is constant relative to everything. Its frequency can change, but its speed is constant. Photons may be absorbed by atoms or release by atoms as energy, but as soon as it ...
0
votes
1answer
60 views

how photon gets accelerated instantaneously to speed of light? [duplicate]

i understand that the photon when emitted is already travelling in the speed of light but how can it go from 0 to speed of light instantaneously. is it because photon is a mass less particle and the ...

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