No.
None. The speed of light is usually assumed to be constant. The symbol used to represent the speed of light is "C", as in E=MC2. Then why is it called a variable speed?
The equation used to determine the speed of light in a given material is v = c / n, where v is the speed of light in the material, c is the speed of light in a vacuum, and n is the refractive index of the material.
The letter "c" is used to represent the speed of light in a vacuum in physics equations.
Pretty close ... that figure is about 99.85% the speed of light. (You used 186,000 miles per second. We used 186,282 .)
In vacuum it is 299792458 metres/second. It is used for light to get from one location to another.
No, a megaphone is a device used to amplify sound, particularly human speech. It does not measure light or speed.
lightyear.
The speed of light, ca. 300,000,000 meters per second.
Light travels at approximately 186,000 miles per SECOND. That is fast. So the expression "faster than the speed of light" is used to describe someone or something that is really fast (but it's not actually faster than speed of light)
It doesn't work that way. The light-year is not used to measure the speed of light. It works the other way round: First, the speed of light is determined through other methods, then the distance called a light-year is calculated based on that measurements.
Light waves - electromagnetic waves that can travel through a vacuum at the speed of light. Radio waves - electromagnetic waves used for communication that travel at the speed of light in a vacuum. X-rays - a high-energy form of electromagnetic radiation that can travel at the speed of light. Microwaves - electromagnetic waves commonly used in technology and cooking that can travel at the speed of light.
Albert Einstein did not determine the speed of light, rather that the speed of light was the maximum speed possible in the universe. The speed of light was discovered in the late 1600's by Danish astronomer Ole Roemer, using Jupiter and its moon Io. It was later used in Maxwell's equations of electromagnetism, and then later used by Albert Einstein in his theory of special relativity.