2007-11-20 12:50:58 · 5 answers · asked by STUDY 3 in Science & Mathematics ➔ Physics
c/n = 300,000km/s / 1.333 = 225000 km/s
2007-11-20 13:00:46 · answer #1 · answered by GusBsAs 6 · 0⤊ 0⤋
Light is slowed down in transparent media such as air, water and glass. The ratio by which it is slowed is called the refractive index of the medium and is always greater than one.
When people talk about "the speed of light" in a general context, they usually mean the speed of light in a vacuum. This quantity is also referred to as c.
The speed of light in air is only slightly less than c. Denser media, such as water and glass, can slow light much more, to fractions such as ¾ and â
of c. Through diamond, light is much slower—only about 124,000 kilometres per second, less than ½ of c. This reduction in speed is also responsible for bending of light at an interface between two materials with different indices, a phenomenon known as refraction.
The index of refraction of some common materials are given below:
Vacuum 1
Crown Glass 1.52
Air 1.0003
Salt 1.54
Water 1.33
Asphalt 1.635
Ethyl Alcohol 1.36
Heavy Flint Glass 1.65
Fused Quartz 1.4585
Diamond 2.42
Whale Oil 1.460
Lead 2.6
Therefore the speed of light in water would be c/1.33
where c = 2.99792458 x 10E8 m/s
2007-11-20 21:02:01 · answer #2 · answered by java2bobby 3 · 2⤊ 0⤋
It is about 225 million meters per second; or about 75% of the speed of light in a vacuum.
The speed of light in any medium is: c/n, where "c" is the speed of light in a vacuum, and "n" is the index of refraction of the medium. For water, the index of refraction is about 1.33.
2007-11-20 21:02:14 · answer #3 · answered by RickB 7 · 0⤊ 0⤋
218,400Km/sec.
This figure is PURE water at STP.
2007-11-24 14:45:24 · answer #4 · answered by Anonymous · 0⤊ 0⤋
218,400 Km/s or 2.184 * 10^8 m/s...
They found it out in an experiment. Thanks for letting me know also... Check out the site below... Hope I've helped you... :D
2007-11-20 21:00:26 · answer #5 · answered by Gerwin 2 · 0⤊ 2⤋