1 and 2 mark questions:
Q1. If an object is placed in front of a concave mirror of 20 cm focal length, what is the position of the object when it will give a real and diminished image?
Q2. An object is placed in front of a concave mirror such that its image also formed at the same place at 10 cm in front of the mirror. What is the focal length of the mirror?
Q3. We wish to obtain an erect image of an object using a concave mirror of focal length 15 cm.
a. What should be the range of distance of the object from the mirror?
b. What is the nature of the image?
Q4. An object is placed in front of a concave mirror such that its image also formed at the same place at 10 cm in front of the mirror. What is the focal length of the mirror?
Q5. At what distance from a concave mirror of focal length 20 cm, should an object 1.5 cm long be placed in order to get an erect image 4.5 cm tall?
Q6. Between which two points of concave mirror should an object be placed to obtain a magnification of m = - 2.
Q7. Why does a concave mirror cannot be used as a rear view mirror in vehicles?
Q8. Two spherical mirrors A and B produce images with linear magnifications + 1.5 and + 0.5 respectively. Identify which one of them is a a convex mirror and why?
Q9. State two effects caused by the refraction of light?
Q10. The refractive index of water with respect to air is 4/3. What is the refractive index of air with respect to water?
Q11. The refractive indices of kerosene, turpentine and water are 1.44, 1.47 and 1.33 respectively. In which of these materials does light travel fastest?
Q12. A virtual, erect and magnified image of an object is to be obtained with a convex lens. For this purpose, where should the object be placed?
Q13. If an object is placed at the centre of curvature in front of a concave lens, what kind of image it will produce?
Q14. A spherical lens has a power of, - 2.5 D. What is the focal length and nature of the lens?
Q15. Explain the spectrum of white light.
Q16. While passing through a prism, which colour deviates least ?
Q17. Why do the stars always appear to be twinkling?
Q18. What is tyndall effect?
Q19. Why does the sky always appear to be blue?
Q20. Name any two effects of atmospheric refraction.
4 mark questions:
Q21. If the magnification of a mirror is +4,
a. What type of mirror is this?
b. If the focal length of the mirror is 5 cm, what is the the object distance? 1 + 3
Q22. Draw a diagram to show the refraction of light through a glass prism. On this diagram, mark (i) incident ray, (ii) emergent ray, and (iii) angle of deviation. 2½ + 1½
Q23. A virtual image at a distance of 20 cm in front of the lens is produced when an object is placed 100 cm from the lens. Calculate (i) focal length of the lens and (ii) magnification produced. (iii) Also calculate the power of the lens. 2 + 1 + 1
Q24. An object is placed at a distance of 6 cm from a convex lens of focal length 4 cm. If the the height of the object is 5 cm, find
(i) position, (ii) nature and (iii) height of the image. 2 + 1 + 1
Q25. An object is placed at a distance of 20 cm from a convex mirror of radius of curvature 60 cm. If the the height of the object is 3 cm, find (i) position, (ii) nature and (iii) height of the image. 2 + 1 + 1
Q26. A real image of 6 cm height is produced when an object of 2 cm height is placed at a distance of 16 cm from a concave mirror.
(i) what is the focal length of the mirror?
(ii) find the position of the image? 2 + 2
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