Light — Lenses

Grade 10 Science — Light — Lenses: 25 practice questions with instant scoring and explanations.

1. A convex lens is also called:
2. A concave lens is also called:
3. The lens formula is:
4. Power of a lens is defined as:
5. The SI unit of power of lens is:
6. A lens of power +2 diopters has focal length:
7. For a convex lens with f = 20 cm, u = 30 cm, find v using 1/f = 1/v - 1/u:
8. Magnification produced by lens is:
9. A concave lens always produces:
10. A convex lens produces real image when object is:
11. The lens maker's equation is:
12. For a convex lens in air with focal length 20 cm, power in diopters is:
13. A convex lens of focal length 10 cm produces magnification -2. Object distance is:
14. When object is at focal point of convex lens, image is at:
15. A concave lens with power -4 diopters has focal length:
16. Two convex lenses of focal length 10 cm each are in contact. Combined focal length is:
17. For a convex lens with u = 40 cm and f = 10 cm, magnification is:
18. A convex lens acts as magnifying glass when object is:
19. Which combination of lenses is used in telescopes to magnify distant objects?
20. For a biconvex lens, both radii are positive. The focal length is:
21. A concave lens with f = -15 cm and object at u = 30 cm has image at:
22. For a compound lens system, the total power is:
23. Which lens is used in cameras to focus on objects?
24. A convex lens produces virtual image when object is:
25. The magnification of +3 means image is: