Does light travel fastest through a solid or air?

Answer 1

Light travels faster through a gas. In general, as the density of a material increases the velocity which light will travel through it decreases.

Answer 2

Short Answer:

Light generally travels faster in gasses than in liquids or solids. There is no

general rule as to whether the speed of light in solids will be faster or slower than

in liquids.

Long Answer:

The speed of light in vacuum, c, is related to the speed of light in a material, v, is given by the index of refraction, n, of the material.

v=c/n Normally, gases have an index of refraction very nearly equal to unity, hence the

speed of light is very close to the speed of light in a vacuum.

Liquids and solids tend to have an index of refraction substantially larger than

unity, i.e. 1.1 to 1.7 or higher. As a result, we know the speed of light is much

lower in most solids and liquids.

There is no general statement that can be made comparing light speed in liquids

or solids. Sometimes it is higher and sometimes lower.

Caveat:

To explain why a particular material has a particular index of refraction (and

hence a particular value for the speed of light) one has to characterize the

electronic structure and response of the electrons in the material to the

electromagnetic fields of a light wave. This is not simple.

For many materials, light does not travel much at all and just gets absorbed. In

such a case, it is tricky to define the speed of light, but it can be done. That too

is not so simple.

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Observation #1 on the Long Answer:

The index of refraction is a description of the speed of light in the substance.

The Long Answer teeters uncomfortably close to the implication that the index

of refraction is somehow its cause.

Answer 3

The speed of light is constant and is not affected by the material through which it travels. The speed of light is only constant in a vacuum

Speed of the light in vacuum is 300000000 metres per second

Answer 4

Air. Light has the highest speed in a vacuum (about 300,000 km/sec), and is only slightly slower in air. However, in a solid, it can be quite a bit slower. For example, the speed of light in glass (as when it is used for fiber optics), the speed is only about 2/3 the speed of light in a vacuum (so, that would be about 200,000 km/sec).

Answer 5

In air the speed is high.