1. A biconvex lens made of a transparent material refractive index 1.25 is immersed in water of refractive index 1.33. Will the lens behave as a converging or a diverging lens? Give reason.
2. A biconvex lens made of a transparent material of refractive index 1.5 is immersed in water of refractive index 1.33. Will the lens behave as a converging or diverging lens? Give reason.
3. A convex lens is placed in contact with a plane mirror. A point object at a distance of 20 cm on the axis of this combination has its image coinciding with itself. What is the focal length of the lens?
4. Write the relationship between angle of incidence i, angle of prism A and angle of minimum deviations from a triangular prism.
5. How does focal length of a lens change when red light incident on it is replaced by violet light? Give reasons for your answer.
6. Name the physical quantity which remains same for micro waves of wavelength 1 mm and UV radiation of 1600 A in vacuum.
7. Under what condition, does a biconvex lens of glass having a certain refractive index act as a plain glass sheet when immersed in a liquid?
8. For the same value of angle of incidence, the angle of refraction in three media A, B and C are 15°, 25° and 35° respectively. In which medium, would the velocity of light be minimum?
9. When monochromatic light travels from one medium to another, its wavelength changes but frequency remains the same. Explain.
10. The refractive index of diamond is much greater than that of glass. How does a diamond cutter make use of this fact?
11. If a ray propagates from a rarer to a denser medium, how does its frequency change?
12. State the criteria for the phenomenon of total internal reflection of light to take place.
13. A lens behaves as a converging lens in air and a diverging lens in water (g = 4/3). What will be the condition on the value of refractive index (g) of the material of the lens?
14. A converging lens axially in contact with a diverging lens; both the lenses being of equal focal length. What is the focal length of the combination?
15. A glass lens of refractive index 1.45 disappears when immersed in a liquid. What is the value of refractive index of the liquid?
16. Calculate the speed of light in a medium whose critical angle is 30°.
17. Why does the sky appear blue?
18. Under what condition does the formation of rainbow occurs?
19. Two thin lenses of power +6D and -2D are in contact. What is the focal length of the combination?
20. Two thin lenses of power + 4D and -2D are in contact. What is the focal length of the combination?
21. Two thin lenses of power +5D and -2.5D they are in contact what is the focal length of the combination?
22. Why are convex mirrors used as side view mirrors in cars?
23. A converging lens of refractive index 1.5 is kept in a liquid medium having same refractive index. What would be the focal length of the lens in this medium?
24. How does the power of convex lens vary if we incident red light is replaced by violet light?
25. Explain giving reason why the sun looks reddish at sunrise and sunset?
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