Is light made up of photons or electromagnetic waves?

Answer 1

Your question is to early to be answered, several experiments have been done, concerned to this field, so the light behaved as a wave in some and behaved as particle in the others.
It stills confusing.

Answer 2

When light is emitted from matter, it is in the form of photons. Photons are elementary particles of electromagnetic radiation which have an energy E=hv, where E is the photons energy, v is the frquency of the electromagnetic wave it can produce and h is Planks constant. This equation encompasses the particle/wave duality as E is the energy of a particle and v is the frequency of a wave.

The photon itself can be thought of as wave packets, which can come together with other photons to form an electromagnetic wave that has an intensity proportional to the number of photons being emitted. This wave will experience all the normal effects of wave behavior such as reflection (e.g. from mirrors), refraction (e.g. from lenses) & diffraction (e.g. double slit experiment), but the photons which made it up still exist as part of the wave.

When the wave is absorbed by a surface, the photons may exhibit their particle behavior again by colliding with electrons and producing an electrical current. This is the photoelectric effect.

If it were possible to perform the double slit experiment with light intensity so low that photons would pass through the slit one at a time, it would not be possible to observe the results as the process of measuring the photon actually nullifies the information being measured. This is because of the uncertainty principle, which prevents quantites such as position and momentum being defined simultaneously. In wave type situations, particle distribution can only be considered as a probability function.

Answer 3

Light energy is quantized. That means it comes in small, discrete [individual] packages. This package is called the photon.
The properties of a photon are somewhat counter-intuitive.
It has no mass but it does contain momentum.
As it moves through space it generates a self perpetuating electromagnetic oscillation, the field of which contains the photon's energy. The quantity of energy determines how quickly the oscillation occurs. This gives the photon two further properties. A frequency and a wavelength. Then it gets wierd.

Experiment shows that this wave behaves classically. Reflection, refraction, diffraction, interference and the like. However, it only behaves like this as long as you don't observe it. The reason for this is the act of looking imparts influence on the precedings [remember, if you look using light, the light you use will impart momentum of its own and change what you're looking at]
In this situation, the photon acts like a pointlike particle which exists somewhere within the wavelength defined by the electromagnetc wave. The strength of the electric field determines the relative probability of finding the photon at that point if you look there.

It all sounds rather insane and unecessaritly complicated. Nobody can suggest why photons have these properties or what the photon itself is. All they know is that the universe is full of them and it [the universe] wouldn't work unless the photon behaved as it does.

I prevent myself from getting a headache by considering 'light' to be a photon contained in an electromagnetic wave. This is wrong but it helps me visualise it.
It's nice and wavey if I leave it to do it's stuff but as soon as I start messing with it's 'mojo' [by tying to see what its up to] it becomes a particle.

Answer 4

Good question.
Look up Young's double split experiment. A light beam is aimed at a screen through a very small hole. If there is only one hole, the light gos through it and hits a screen at the back as would be expected if light was made of photons.
If there are two holes however, the light interferes which each other like waves do.

Also look up Loius de Broglie's equation. It shows how to convert the properties of a particle to find its wavelength (and vice versa.)

Answer 5

Light is an electromagnetic wave and it is made up of photons.

All kind of particles - photons, electrons, protons, neutrons, whole atoms - they all behave like waves depending on the situation. Light usually behaves like waves. The wave nature of normal matter on the other hand is only visible in certain experiments.

Answer 6

photons are the quanta, or small units of which light is composed. their existence is widely accepted and has been established by empirical investigation.

light, and therefore photons, like all forms of electromagnetic radiation, exhibits wave-particle duality.

this means that under our current understanding of physics, the photon, of which light is composed, exhibits both particle characteristics, and the characteristics associated with electromagnetic waves.

we make take this to mean that photons are at once both particles and waves, or that there is something missing from our current understanding.

essentially if you set up an experiment to measure the wave properties of photons, then they behave like waves, but if you set up another experiment to measure the particle characteristics, then they behave like particles.

there is an explanatory video in the first link:

http://science.howstuffworks.com/light.htm

http://en.wikipedia.org/wiki/Wave-particle_duality

Answer 7

Light is made up of photons, full stop. Photons are packets (quanta) of electromagnetic radiation presenting as standing waves. Imagine a porpoise swimming in a pool being carried on the back of a giant turtle swimming in direct line between two islands

The porpoise swims endlessly in circles, but never stops being a porpoise, eventually, however, it arrives at the second island having travelled in a straight line.

Answer 8

Albert said that light is a stream of energy packets called photons, having no mass, and pulsating with electromagnetic energy. Some scientists believe, fervently, that quantum electrodynamics (QED) is not a complete description—there will be a better way.

Lower energy EM waves, like radio waves, act more like waves, while higher energy waves, like X-Rays, behave more like particles. http://imagers.gsfc.nasa.gov/ems/waves4.html ********************************************************************
Previous Yahoo Best Answers:
enufwork:
Did someone suggest that those were different theories? It is really just different aspects of the same phenomenon... a good analogy is a cylinder. From one direction you see a circle and from another a rectangle. Both the same object, just a different view.
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iceni:
Light consists of elementary particles called photons. A photon can have both particle & wave properties depending on the observer. In fact, a photon will have both properties until it is observed.
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Answer 9

light probably isnt made up of both or photons and waves. its one or the other as althougth they have similar properties, they are essentially different. if this was the case they'd be two types of "light".
there are agruments for photons making light, and arguments for waves making light, which are covered in quantum physics. for example light refracts as do waves i.e. if u drop a pebble in water. althougth some argue light must be a stream of photons, with the eject of these photons from atoms creating the energy for "light".

Answer 10

According to quantum mechanics, light behaves as both a wave and a particle, depending on the circumstances it is put under. Try making slits in paper not very far apart, and shine a laser through them. You will see that different slits will show different degrees of brightness, which is the behavior of a wave. However, if you study the equatons given for light carefully, you will see the behavoir of a particle as well.