What is speed of light affected by?

Answer 1

The speed of light is defined as being through a 'VACUUM'.

If it passes through any material object it will slow down. It will slow down on passing through air.

It will come to a complete stop when it tries to pass through a brick wall; because you cannot see light on the other side of a brick wall.

The defined speed is 299,792,458 m/s in a vacuum.

Given as an approximation as 3.0 x 10^(8) m/s in a vacuum, or 3,0 x 10(6) km/s. In words ' three million kilometres in one second'.

Answer 2

The speed of light depends on the medium through which it passes. The fastest that light can travel is the speed of light in a vacuum (c), which is 299,792,458m/s. The permittivity and permeability of the medium through which it passes are what reduces the speed of light.

For example, while the speed of light in air can be simplified to being approximately 3*10^8m/s, in an optical fibre, it is reduced to approximately 2*10^8m/s, that is, two thirds of it's speed in a vacuum.

Light will easily propagate through an insulating medium, though will not do so through a conductor, as the electric and magnetic fields generated by the electromagnetic radiation will interact with those of the conductor.

Answer 3

The speed of light in a material substance depends on the material it's traveling through. It's slower in substances with higher indices of refraction. The speed of light in a vacuum is a fundamental physical constant which as far as we can tell doesn't depend on anything, it just is what it is.

Answer 4

The ratio between the two (the speed of light and the speed light actually travels through a transparent medium) is the refraction index, but the slow down is determined by the permittivity and permeability of the medium.

Answer 5

It depends on the electrical characteristics of space, that is, the electrostatic permittivity

and magnetic permeability. The speed of light in space is the reciprocal of the square root

of the product of those two properties of vacuum.

Those are the characteristics of every medium that determnine the speed of light in it.

Answer 6

The speed of electromagnetic radiation is determined by the electrical characteristics
of the material it's traveling through ... specifically, the electrostatic permittivity and
the magnetic permeability. Those numbers are different for every material. The speed
of light in the material is 1/(the square root of their product) .

Answer 7

Whatever light is traveling through, whether vacuum or some material medium,

its speed depends on the electrical characteristics of that environment, specifically

its electrostatic permittivity and magnetic permeability.

Those are measurable properties of empty space and of any substance. The

speed of light through it is the reciprocal of the square root of the product

of those quantities. Which shouldn't be too surprising, since we know now

that light and other electromagnetic waves consist of traveling electrostatic

and magnetic fields.

Try it for yourself. The electrostatic permittivity of free space (vacuum) is 8.9 x 10-12 coulomb/newton-meter2 and its magnetic permeability is 4 pi x 10-7 weber/ampere-meter.

Note: 1 weber = 1 newton-meter/ampere

and, if you need them, 1 newton = 1 kilogram-meter/second2

1 ampere = 1 coulomb/second

Answer 8

Yes, slightly, because the refractive index of air depends somewhat

on the air temperature (as well as the pressure and humidity).