What are the properties of light?

Question

I mean, when we see any light, what properties can we measure and understand. For e.g. i know that light has "frequency", "amplitude" ..... similarly what else does it have?

1. If we have two identical light source one 2 kms away another 5 kms away, what property of light tells the distance of the source?

2. what is the frequency spectrum of "electro magentic radiation" and what is that of "visible light"?

Answer 1

The frequency (lenght of the wave) can tell you about the amount of energy that light (electromagnetic radiation) carry. The shorter the wave, the more energy is carried by a proton. When you observe two distant objects that have identical light you can tell if they are moving or not. It's because when something is in motion it's light frequency seems to be greater (when it goes towards you) or lower (when it runs away). Observing a light emitted by stars or reflected by planets we can say what they are made of, because different substances reflect (or emit) different frequencies of radiation. As they are mixed we only see white light, but using a prism it's possible to separate it.

If we want to tell the distance of the source that's emitting light and is not in motion I think the only think we can do is to measure the brightness. But I know that, knowing that the universe is spreading, scientists measure distances to remote stars, because the greater is the distance the faster they are moving (in relation to us)

The spectrum of visible light is from 400 to 700nm (wave lenght).Radiation above 700 or under 400nm (infrared, ultraviolet, radio waves, microwaves, X-rays etc) is invisible.

Answer 2

Light is a flux of UfO s in simple language.because no one really knows what its made of. On planet Earth the frequency of light in the horizontal direction is more bluish than the overhead direction.(this fact was about sky fluorescence wAS DISCOVEREDby Ralph Rene in 1985)
The frequency at which light moves determines the Power of the radiation flux. A very plausible explanation about the nature of light was not given by Einstein but was given by Milton W. Monson.(An esoteric fact).
Light has never been proven to be electrical nor magnetic nor a combination of both. However it does respond to a magnetic energy. As was shown by the Zeeman Effect.The electromagnetic spectrum is split in half when light is subjected to a magnetic field.
The Human Eye is structured to respond to the radiaion power which indicated the colors reflected by an object.The density of the light flux is in lumens per meter square . That tells you the strengtht and intensisty of light.LASER beam is a good example of coherent radiation results in a very high light power intensitY.
Mathemathically the intensity of a light source is inversely proportional to the square of the distance from its source.Light when traveling thru the air or any other medium is subject to speed changes . LIght velocity is by no means constant.

The visible spectrum to the human eye is in the order of 10^14 herz.It vary among animals and insects.

Answer 3

The properties of light will not necessarily tell you that distance, although you could work it out with some hard math.
The best way to tell the difference would be in the intensity that meets your eye, or sensor, the loss of intensity is mostly due to refraction in the atmosphere.
2 - All light is in the electromagnetic radiation, that is a proper name for light. But, the visible spectrum (red through violet) lies around 400nm-700nm.
You can check out more about this at http://en.wikipedia.org/wiki/Visible_light

Answer 4

Light have amplitude? I don't think so, if there is, then sound may produced. the frequentcy of the light is between the infared, and ultraviolet.

1. Mirage, I thought.

2. the frequency spectrum of "electro magentic radiation" is higher than the visible light and visible light is the light that we can see with our naked eyes

Answer 5

Read a basic physics text book. Preferably by Feynman.

Just looking at the light one can not measure the distance just focusing via telescope we could approximate