CBSE Guess > Papers > Important Questions > Class X > 2008 > Science > Science By :- Nagesh Kumar

Science - Light Refraction and Refraction Human Eye and The Colourful World

1. An object is placed at a distance of 10cm from a convex mirror of focal length 15 cm. find the position and nature of the image.
2. What do you understand by the principal focus of a concave mirror?
3. Why do we prefer a convex mirror as a rear-view mirror in vehicles
4. The refractive index of diamond is 2.42. What is the meaning of this statement?
5. What is the difference between real and virtual images?
6. What are the uses of a concave mirror?
7. What is the property of image formed by a concave lens?
8. Name the three primary colours?
9. For which colour the refractive index of material is maximum?
10. Find the focal length of a convex mirror where radius of curvature is 32 cm.
11. Find the power of a concave lens of focal length 2m.
12. What is refraction of light? Write a law of refraction.
13. A doctor has prescribed a corrective lens of power + 1.5 D. Find the focal length of the lens. Is the prescribed lens diverging or converging?
14. An object 5 cm in length is held 25 cm away from a converging lens of focal length 10cm. Draw the ray diagram and find the position, size and nature of the image formed.
15. Define reflection of light.
16. What happens to the light when it travels from denser to rarer medium?
17. Where will the image be formed when an object is placed between the pole and focus point of the mirror?
18. What colour we obtain when we mix red and green?
19. What is short sightedness or myopia? What causes myopia? How is myopia corrected?
20. Why does it take some time to see objects in a dim room when you enter the room from bright sunlight outside?
21. What is Presbyopia? How is it corrected?
22. Define dispersion and spectrum?
23. What happens to the image distance in the eye when we increase the distance of an object from the eye?
24. Why does the sky appear dark instead of blue to an astronaut?
25. In an eye, where is image formed?
26. What is iris?
27. Cinematography is based on which principle?
28. The far point of a myopic person is 80cm in front of the eye. What is the nature and power of the lens required to correct the problem?
29. What do you understand by power of accommodation of the eye?
30. Define least distance of distinct vision.
31. Why do stars twinkle?
32. How will you say that white light of the sun is made of seven colours?
33. Where is far point located for a normal eye?
34. Cylindrical lenses are used to correct which type of defects of vision?
35. Hypermetropia is corrected by which type of lens?
36. What is the cause of cataract?