REFRACTION OF LIGHT.................pptx

REFRACTION OF LIGHT.................pptx

1. REFRACTION OF LIGHT ARCHA S R BEd Physical Science

2. THINGS TO REMEMBER… When light travels through single medium When light enters obliquely from one medium to another When light enters normally from one medium to another path of light will be straight line it undergoes deviation. It do not undergoes deviation

3. OPTICAL DENSITY The ability of a medium to influence the speed of light through the medium is its optical density. OPTICALLY DENSER MEDIUM -mediums with higher optical density eg ; Diamond In these mediums, speed of light is lower OPTICALLY RARER MEDIUM -mediums with lower optical density eg ; air In these mediums, speed of light is higher Air>Water>Glass>Diamond

4. Don’t you remember this……..?

5. Before pouring the water AFTER POURING THE WATER There is no deviation for the ray of light falling on the eye from point B The straw appears bent, as the actual position B seems to have risen to the position C.

6. Refraction When a ray of light enters obliquely from one medium to another of different optical densities, it undergoes a deviation at the surface of separation of the mediums. This phenomenon is refraction. - The ability of light to undergo refraction in a medium depends on the optical density of the medium.

7. Refractive Index It is the ratio of speed of light in vaccum to the speed of light in the medium. Refractive index n = refractive index c = speed of light in vaccum v = speed of light in medium   The speed of light in vaccum (c) =  

8. Find the refractive index Diamond 2.24

9. Relation between refractive index and speed of light Refractive index increases , speed of light decreases . Optical density increases , speed of light decreases . Optical density increases , refractive index increases .

10. Answer the questions. How does the direction of light change when a ray of light enters obliquely from air to water? (deviates towards the normal/deviates away from the normal) How does the direction of light change when a ray of light enters obliquely from water to air? (deviates towards normal/deviates away from the normal)

11. When light enters from one medium to another, the incident ray, the refracted ray and normal at the point of incidence, will be on same plane. When light enters from an optically rarer medium to a denser medium, it deviates towards the normal

12. When light enters from an optically denser medium to a rarer medium, it deviates away from the normal.

13. A ray of incident normally at the surface of separation of mediums does not undergo refraction.

14. THANK YOU