Why does the light ray bend as it passes from air to glass or from air to water?

Answer 1

Light bends towards the normal when it touches glass or water because the light travels from optically rarer medium to optically denser medium. Here, air is optically rarer medium and water or glass is optically denser medium. Light slows down in the denser medium. As one end of the wave front hits the interface before the other, we get a turning effect, just as when people march in a line abreast the line will bend if the people at one end slow down.

Answer 2

If light travels straight through a glass of water, it slows down. If light travels through a glass of water of an angle, the light that hits the closer edge will slow down sooner than the light that hits the further edge. This causes the light to bend in the direction of the closer edge. Imagine a troop of soldiers marching in formation. If they hit a patch of rough terrain, the soldiers will slow down. If they hit the rough terrain at an angle, and they only slow down when the hit rough terrain, then the soldiers will change direction, because some are slowing down, and some aren't.

Answer 3

Refraction is related to the fact that light has a different speed in different media (in this case, air and water). The more detailed explanation requires an understanding of the Huygens-Fresnel principle. Check the corresponding Wikipedia article if you want more details.

Answer 4

When light encounters the glass in a lens what happens?

Answer 5

That is related to the fact that light moves slower in glass or water. You can find some details in the Wikipedia article on "refraction".

Answer 6

Water doesn't refract more light than glass...

Answer 7

because the glass is more dense than the air that why the ray would bend towards the normal