I learnt from this particular topic that,when the light moves from air to glass,it is refracted towards the normal & when the light moves from glass to air,it is refracted away from the normal.
And also that light from an object bends as it comes out of water ; but our brain thinks the light has moved in a straight line. So, the object appears to be at a higher position than it actually is.
& to summarise the key points :
Light is bent or refracted when it passes from one transparent material into another,such as from air to glass and vice versa.
Two effects of refraction are (a)an object in water appears nearer to the surface than it really is and (b)an object such as a stick placed in water appears to be bent.
Refraction is responsible for image formation by lenses and the eye.
The Snell's Law :D
In 1621, a Dutch physicist named Willebrord Snell (1591-1626), derived the relationship between the different angles of light as it passes from one transperent medium to another.
When light passes from one transparent medium to another, it bends according to Snell's law which states:
Ni * Sin(Ai) = Nr * Sin(Ar),
where: Ni is the refractive index of the medium the light is leaving, Ai is the incident angle between the light ray and the normal to the meduim to medium interface, Nr is the refractive index of the medium the light is entering, Ar is the refractive angle between the light ray and the normal to the meduim to medium interface.
*Information taken from,
www.google.com.sg :
http://www.ps.missouri.edu/rickspage/refract/refraction.html
http://hyperphysics.phy-astr.gsu.edu/Hbase/geoopt/refr.html
& the science textbook.
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