Refraction of Light ppt

2. Examples from daily life

5. Points to remember
 When a ray light passes from air to water its speed changes. Due to this
there is a change in direction of the ray
 The change in direction suffered by a ray of light as passes obliquely from
one optical medium to another with different optical densities is known as
refraction
 When a ray of light is incident on a surface separating two media a small
fraction of light always get reflected.
 Refraction can make an object appear to be on a different position

6. Why does light refract?
Why does light refract?

7. when a ray of light goes from an optically rarer medium to an optically
denser medium, the speed of light decreases and the light ray bends towards
the normal.

9. When a ray of light travels from a denser medium to a rarer medium, the ray
of light bends away from the normal.

10. Refraction through a glass slab

11. Effects of refraction

14. Twinkling of stars

15. Variation in the size of sun at dusk,
dawn and at noon.

16. Refractive index
• The ability to refract light is called refractive index.
• Refractive index of a medium is equal to the ratio of speed of light in
vacuum to the speed of light in that particular medium
• This ratio is a constant for a given pair of media.
• It is represented by a greek letter ‘μ’

17. Snell’s law of refraction

18. Thank you