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Is light a particle which has a electromagnetic field around it OR does the particle itself travels in a wave like motion? IS it just the EM field which moves in a wavy motion like ripples?

(Please don't mark it as duplicate as i didn't understand other answers that's why i am hoping for a better explained answer without any mathematical notions)

Qmechanic
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Bhavesh
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    It's neither... but the real explanation is hard to understand. For certain cases you can treat light as a particle and for others like a wave and for some it's neither. The best book suggestion I can offer to you is probably Feynman's "QED: The Strange Theory of Light and Matter". I don't think one can explain the real facts on this level much better than Feynman did. – CuriousOne May 03 '15 at 05:57
  • Which other answers? – Qmechanic May 03 '15 at 07:04
  • Hi Bhavesh, I've linked a duplicate that answers your question and contains no maths. – John Rennie May 03 '15 at 07:58
  • @JohnRennie in your answer of http://physics.stackexchange.com/questions/90646/what-is-the-relation-between-electromagnetic-wave-and-photon do you mean that it has not been discovered whether light is a photon or wave? – Bhavesh May 03 '15 at 10:11
  • My answer says: Light is not a wave nor a particle but instead it is an excitation in a quantum field. – John Rennie May 03 '15 at 10:12

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Is light a particle which has a electromagnetic field around it OR does the particle itself travels in a wave like motion?

The latter. Light consists of electromagnetic waves which have a quantum nature, wherein we say the photon is a quantum of light. This tends to get converted into a "particle" of light wherein people think of the photon as some point-particle thing. But see Wikipedia where you can read that the energy and momentum of a photon depend only on its frequency (ν) or inversely, its wavelength (λ):

$E=\hbar\omega=h\nu=\frac{hc}{\lambda}$

A photon has a wavelength, it is a wave. However when you detect a photon on say a screen, what you see is a dot. See the Wikipedia double-slit article for that. But just because you see a dot when you detect a photon, don't think it's some point-particle. It isn't. It's a wave, with a wavelength. (For myself I think it's best to think of detection as something akin to an optical Fourier transform, but that's one for another day.)

Is it just the EM field which moves in a wavy motion like ripples?

Kind of. Like HolgerFiedler said, photons are disturbances in the EM field. And like Maxwell said, "light consists of transverse undulations in the same medium that is the cause of electric and magnetic phenomena". IMHO it's important to appreciate that the quantum nature of light is associated with its wave nature. See Leonard Susskind talking about the Higgs boson in this video? At 2 minutes 50 second he rolls his whiteboard marker round saying angular momentum is quantized. Take a look at some pictures of the electromagnetic spectrum. Notice how the depicted wave height is the same regardless of wavelength? And you doubtless know that a sine wave is associated with rotation? The quantum nature of light is to do with that. Roll your marker round fast or slow, but roll it round the same circumference, because Planck's constant of action h is common to all photons regardless of wavelength.

John Duffield
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Is light a particle which has a electromagnetic field around it OR does the particle itself travels in a wave like motion?

This depends of what you want to calculate. For atomic processes one use QED and photons are disturbances in EM field existing everywhere. But really one calculate processes in atomic and subatomic dimensions.

If one want to explaine how EM radiation works it is the best way to think about emission and absorption of photons. Unfortunately this simple point of view is overshadowed by QED point of view. be sure that light travels as a lot of photons.

Each photon oscillate with its electric and magnetic field..

Community
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HolgerFiedler
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  • The photon picture is almost completely useless for EM calculations. It helps to visualize atomic and molecular physics processes, where the main players are atoms and molecules, but it has next to nothing to say about light itself. Individual photons do not have fields associated with them. They are simply the quanta of a quantum field. That field, unfortunately, does not exist on its own, it only makes sense if we also allow for charged particle states that it couples to, and then we are basically in the thick of QED. – CuriousOne May 03 '15 at 06:33
  • @CuriousOne Have a look at http://motls.blogspot.com/2011/11/how-classical-fields-particles-emerge.html . The wave functions constructed for photons use A the potential of the Maxwell equations and the differentials as operators. Thus the photon has in its probabilistic mathematical form the seeds of the electric and magnetic fields, even without other charged particles around – anna v May 03 '15 at 08:17
  • @annav: photons don't have a wave function. The quantum field has a wave function. That thing tells you how many photons you can count in any given point at a given time. The photon is the measurement, like the spin up/down of an electron is the measurement in single particle theory. – CuriousOne May 03 '15 at 08:50
  • @CuriousOne QFT is one side of it. I have seen it described as the wave function. – anna v May 03 '15 at 08:55
  • @annav: I have also seen Kepler ellipses described as epicycles. That doesn't mean they make sense. You can do classical electrodynamics and you can do QFT. There is no working theory "between" the two. – CuriousOne May 03 '15 at 09:03
  • @annav do you mean that light is neither a wave nor a particle? – Bhavesh May 03 '15 at 10:16
  • @CuriousOne do you mean that light is neither a wave nor a particle? – Bhavesh May 03 '15 at 10:16
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    @Bhavesh: Light and matter are strictly quantum mechanical phenomena. The best way to think about quantum mechanics is that it is neither a particle nor a wave phenomenon. One can derive particle-like and wave-like effects from quantum mechanics, but it is a very distinct third way. The wave-particle duality discussion that you keep hearing about in the media hasn't existed in that form in the physics community for about 70 or 80 years now. It's an anachronism that one shouldn't take seriously. Learn to say "there can always be a third way" and you will have a lot of fun with physics. – CuriousOne May 03 '15 at 10:24
  • @CuriousOne : see The Maxwell wave function of the photon by Raymer and Smith. Whilst there's no working theory between QED and classical electrodynamics, I share anna v's sentiment. IMHO one can see how they relate to one another. – John Duffield May 03 '15 at 12:36