All Questions
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Massive equivalent of a photon and deduction of a photon's linear momentum
Since photons have an energy given by $E=h\nu$, we could define a particle whose rest mass is such that it has the same energy than the photon: $E=m_0c^2 \Longrightarrow m_0=\frac{h\nu}{c^2}$. We now ...
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What is the gravitational pull of a photon? [duplicate]
I know it may seem like a stupid question, but I recently found out that because a photon has energy (obviously) then it must have a gravitational pull. I was wondering exactly what this gravitational ...
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If incoming photons increase the mass and gravity of a black hole are they then some kind of source of gravity? [duplicate]
If incoming photons increase the mass and gravity of a black hole are they then some kind of source of gravity?I can not understand why equivalence of mass and energy lead as to say mass and energy ...
- 1,815
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Does the speed of light in our definitions take vacuum energy into consideration?
We know that the speed of light decreases as it goes through a medium, and we also know that there is a certain vacuum energy that creates a sea of particles coming in and out of existence, which, ...
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3
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Do photons really have kinetic energy?
I haven't found a satisfactory answer to this question.
In special theory of relativity
$$E=\sqrt{m_{0}^2c^4 + p^2c^2}.$$
When we consider photons where $m_{0}=0$ then $E=pc$ but we also know that ...
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If you could bottle a photon would it have mass? [duplicate]
Ok. A photon has no rest mass for the good reason that it has no rest energy. But what about a standing wave? There is fair belief that particles are standing waves, so perhaps nothing rests.
So. ...
Blame
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4
answers
120
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Energy vs. mass in photons
I am confused about the following:
Mass is condensed energy. A photon has no mass, but it has a degree (of quantised) energy. Does that mean it does not have enough energy for it to be condensed ...
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Light absorbed by black holes why? [duplicate]
Why is light absorbed by black holes while it is massless as theory of gravitation works only for masses?
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3
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Justification of $P_{\text{photon}}=E/c$ in derivation of $E=mc^2$
I recently was reading up on the derivation of $E=mc^2$. Now, I came across this derivation at this link. I noticed that several lines into the derivation they throw in the equation
$$P_{\text{photon}}...
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2
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How can a photon have energy when its mass is zero? [duplicate]
How can a photon have energy when its mass is zero? According to Einstein's equation $E = mc^2$ energy depends on $mass*c^2$ Light has zero mass so the energy would be zero too but solar cells use ...
- 1,925
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How can a photon exist on its own without a mass? [duplicate]
For example, thermal energy exists and has no mass, but is carried by particles which have mass. A photon is described as a particle - how can a photon exist on its own, travel in space and even push ...
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9
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How can gravity affect light?
I understand that a black hole bends the fabric of space time to a point that no object can escape.
I understand that light travels in a straight line along spacetime unless distorted by gravity. If ...
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3
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Is light affected by gravity? Why? [duplicate]
I would like to know if light is affected by gravity, also, I would like to know what is the correct definition of gravity:
"A force that attracts bodies with mass" or "a force that attracts bodies ...
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Does $E = mc^2$ apply to photons?
Photons are massless, but if $m = 0$ and $E=mc^2$, then $E = 0c^2 = 0$. This would say that photons have no energy, which is not true.
However, given the formula $E = ℎf$, a photon does have energy ...
user1313
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6
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Do photons gain mass when they travel through glass?
Please correct me if I'm wrong, but I believe that photons slow down when travelling through glass. Does this mean they gain mass? Otherwise, what happens to extra kinetic energy?
I understand now ...
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