✔ 最佳答案
**...=causes of why medium has its affect on the speed
Refraction is the change in direction of a wave when it moves into a new medium which causes it to travel at a different speed*. A wave which has undergone refraction is called a refracted wave. Its wavelength* increases or decreases* with the change in speed, but there is no change in frequency.
**Its wavelength.
**The amount of which has refracted.
When light rays move into a new medium, they are refracted according to the laws of refraction of light*. The direction in which they are refracted depends on whether they move into a denser or less medium*(Thus speed changes during this process) and are consequently slowed down or speeded up.
**Its density
Laws of refraction of light:
1.The refracted ray lies in the same plane as the incident ray and normal at the point of incidence.
2.The ratio of the sine of the angle of incidence* to the sine of the angle of refraction* is a constant for two given media.
2008-12-31 20:07:48 補充:
If second medium(for an example, you have a glass on a table, the liquid inside is the second medium) is denser than the first medium(outside the liquid), the light ray slows down and is refracted toward normal. If less dense, ray speeds up and is refracted away from normal.
2008-12-31 20:08:01 補充:
Here normal means line at right angles to boundary through chosen point, eg: point of incidence, point at which incident ray meets boundary(the point which is refracted) and becomes refracted ray.
Hope this would be useful for you :-)
2009-01-01 13:21:33 補充:
Suppose you have a cup of water. So you have air(less dense) and water(denser). When the light waves enter in the water from* the air, the waves slow down because the water is denser than the air(from air to water).
2009-01-01 13:21:37 補充:
This can be reversed respectively. The wave speeds up on entering a less dense medium(from water to air)
2009-01-01 13:27:08 補充:
Regardless to the above, lens can affect the light waves speed as well. By calculating the power of lens: P= 1/f. The shorter the focal length(f), the more powerful the lens. Thus speed up more.
(Note: All regard to the laws of refraction of light)
2009-01-01 20:59:05 補充:
Conclusion: The density of a medium changes the light wave speed
2009-01-01 21:00:43 補充:
Side affects: The amount of which has absorbed can slow the speed down as well
參考: , Illustrated Dictionary of Science, myself, teacher, Illustrated Dictionary of Science, myself, teacher