11. The focal length of a small concave mirror is 2.5 cm. In order to use this concave mirror as a dentist's mirror, the distance of tooth from the mirror should be: 12. 13. a) 4.5cm c) 3.5cm b) 1.5cm d) 2.5cm Under which of the following conditions a concave mirror can form an image larger than the actual object? a) When object is kept at a distance greater than its radius of curvature c) When the object is kept at a distance equal to its radius of curvature b) When object is placed between the focus and centre of curvature d) When object is kept at a distance less than its focal length An object is placed 20 cm in front of a plane mirror. The mirror is moved 2 cm towards the object. The distance between the positions of the original and final images seen in the mirror is: a) 2 cm b) 10 cm c) 4 cm d) 22 cm 14. If the focal length of a convex mirror is 25 cm, what is its radius of curvature? a) 75 cm b) 100 cm c) 25 cm d) 50 cm 15. The focal length of a concave mirror whose radius of curvature is 32cm: a) 22 cm b) 32 cm c) 12 cm d) 16 cm