applicatons of refraction FROM REFRACTION OF LIGHT.pptx

APPLICATIONS OF REFRACTION

1. REFRACTION OF LIGHT ARCHA S R BEd Physical Science

2. Refraction- Practical activities

3. When we move backward while looking at the coin, at a certain point the coin disappears. When water is poured into the trough, the coin could be seen again. It is because when there is water, the position of the coin seems to be raised due to refraction.

4. 1. Disappearing of coin

5. 2. Place a glass slab on the letters in a textbook. The letters appear raised.

6. The light from the letters undergo refraction. So the letters appear raised when light enters from glass to air. We see the letters in their apparent position.

7. 3. We can’t take out a coin from the glass trough filled with water, by looking through any one side of the trough.

8. The light rays undergo refraction. Due to this reason the coin is not seen at the actual position. It is seemed to be raised. Hence we cannot take the coin easily.

9. 4. The bottom of the pond elevated when viewed from a distance than from a nearer point.

10. The light rays from the bottom of the pond travels from water to air when a person view the pond from a distance. So when distance increases the pond appears more elevated.

11. 5. People who engage in bow fishing aim at a point slightly below the perceived position of the fish. Apparent position Actual position

12. The light rays from fish travels through water and air as a result it undergo refraction. Due to the refraction the fisherman sees the fish in the apparent position, which is above the actual position.

13. Atmospheric refraction Twinkle,twinkle little star………… Why do the stars twinkle

14. Why do stars at a greater distance twinkle? Stars appears as point sources of light because they are at a greater distance from the Earth compared to planets. The light coming from the stars reaches our eyes by traversing through the atmosphere. The optical density of the medium through which the light travels goes on changing as the physical conditions (pressure, temperature etc.) of the layers of atmosphere change continuously.

15. Since the rays undergo irregular refraction the light rays from the stars reach the eyes after refracted several times. So the star cannot be seen continuously at the same position.this is the reason for the twinkling of stars.

16. The sun has passed the western horizon. Then how it is visible now?

17. Even after the sun has passed the western horizon, the sun is visible for some more time. Similarly, the sun can be seen a few seconds before it reaches the eastern horizon in the morning. What is the reason?

18. We can see sun a few seconds before it reaches the eastern horizon in the morning because due to change in optical density of atmosphere, refraction occurs and we see the apparent position of sun which is slightly above the actual position. Likewise in the evening we can see sun a few seconds after the sun reaches the western horizon.

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