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THE BEST ACADEMY, UDYAVARA, SUB: SCIENCE (physics), CHAPTER 1: LIGHT- REFLECTION AND REFRACTION, DURATION: 1 hour, I., , Max. marks: 20, , Answer the following questions:, , 4x1=4, , 1. Define principle axis., 2. What is the position of the image when the object is placed between infinity and optical centre?, 3. State snell's law., 4. What is the S.I unit of power of a lens., II., , Answer the following questions:, , 2x4= 8, , 5. Draw the ray diagram of a convex lens when the obeject is placed, a. At 2F1, b. At infinity, 6. Find the power of a concave lens of focal length 2m., 7. A concave lens of focal length 15 cm forms an image 10 cm from the lens. How far is the object placed from, the lens?, 8. 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?, III., , Answer the following questions:, , 4x2= 8, , 9. An object 5.0 cm in length is placed at a distance of 20 cm in front of a convex mirror of radius of curvature, 30 cm. Find the position of the image, its nature and size., 10. An object of size 7.0 cm is placed at 27 cm in front of a concave mirror of focal length 18 cm. At what, distance from the mirror should a screen be placed, so that a sharp focused image can be obtained? Find, the size and the nature of the image., *************************