- #1
indigojoker
- 240
- 0
i have just a question that came to my mind. do photons have to accelerate to the speed of light every time a light bulb is turned on?
Do photons have to accelerate to the speed of light
- Thread starter indigojoker
- Start date
AI Thread Summary
Photons do not accelerate to the speed of light; they are created at that speed due to their zero rest mass. When a light bulb is turned on, photons are produced instantaneously and travel at the speed of light from the moment of their creation. The discussion highlights that, according to special relativity, photons always move at light speed, eliminating the concept of acceleration for them. The analogy of sound waves is used to illustrate that, like sound, photons propagate at a constant speed without needing to accelerate. Ultimately, photons exist only at the speed of light, and there is no initial speed to consider.
- #2
saket
- 168
- 0
good question! 
well.. answer these, and i hope your doubt will be cleared.
1. when you say, "do photons have to accelerate to the speed of light", what are you assuming the initial speed of the photon?
2. do u know that rest mass of a photon is zero?
3. try to calculate, if you know relevant formula, mass of a photon at any speed other than the speed of light.. and you will surely get the answer.
indigojoker said:
well.. answer these, and i hope your doubt will be cleared.
1. when you say, "do photons have to accelerate to the speed of light", what are you assuming the initial speed of the photon?
2. do u know that rest mass of a photon is zero?
3. try to calculate, if you know relevant formula, mass of a photon at any speed other than the speed of light.. and you will surely get the answer.
- #3
indigojoker
- 240
- 0
1. i don't know the initial speed of the photon, that is part of my question
2. yes
3. photons always has to travel a the speed of light due to special reletivity
basically, how do photons accelerate instantaneously to the speed of light? as in, you are in a dark room... thus no photos (in the visible spectrum). Then you turn on the light... electricity excites the filaments in a bulb and photons are produces, are you saying they are produced at the speed of light?
2. yes
3. photons always has to travel a the speed of light due to special reletivity
basically, how do photons accelerate instantaneously to the speed of light? as in, you are in a dark room... thus no photos (in the visible spectrum). Then you turn on the light... electricity excites the filaments in a bulb and photons are produces, are you saying they are produced at the speed of light?
- #4
saket
- 168
- 0
well... i am a student only, and i haven't done a full-fledged course on relativity and/or quantum physics. i think, if u want to discuss it thoroughly, u shud check in higher levels.. this introductory physics won't help u.
still.. what i think is.. consider here the wave nature of the photon.. it will move with the same speed as soon as it is created! (like sound waves emanating from any source: they move with a constant wave speed, they do not accelerate to that speed.)
and, look at the third part of ur answer.. photons always have to travel at the speed of light! so where comes the question of, "accelerating".
still.. what i think is.. consider here the wave nature of the photon.. it will move with the same speed as soon as it is created! (like sound waves emanating from any source: they move with a constant wave speed, they do not accelerate to that speed.)
and, look at the third part of ur answer.. photons always have to travel at the speed of light! so where comes the question of, "accelerating".
- #5
indigojoker
- 240
- 0
well, how did they originally get to the speed of light if they did not accelerate to it? or maybe it's instantaneous acceleration... maybe i shouldn't post this in the HW section since this was just a thought...
- #6
saket
- 168
- 0
think: what was being accelerated? (if u even think that there was an instantaneous acceleration!)
There can be no photon below the speed of light! It's created with the speed of light only.
There can be no photon below the speed of light! It's created with the speed of light only.
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I'm not able to figure out, why my solution is wrong, if it is wrong .
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook.
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I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
I can't figure out how to find the velocity of the particle at 37 degrees. Basically the bead moves with velocity towards right let's call it v1. The particle moves with some velocity v2. In frame of the bead, the particle is performing circular motion. So v of particle wrt bead would be perpendicular to the string. But how would I find the velocity of particle in ground frame?
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