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Lenses and Mirrors
____ 1. You stand two feet away from a plane mirror. How far is it from you to your image? a. 2.0 ft c. 4.0 ft b. 3.0 ft d. 5.0 ft
____ 2. Which of the following best describes the image from a plane mirror? a. virtual and magnification greater than one
c. virtual and magnification equal to one
b. real and magnification less than one d. real and magnification equal to one
____ 3. When the reflection of an object is seen in a plane mirror, the image is: a. real and upright. c. virtual and upright. b. real and inverted. d. virtual and inverted.
____ 4. When the reflection of an object is seen in a concave mirror the image will: a. always be real. c. may be either real or virtual. b. always be virtual. d. will always be enlarged.
____ 5. When the reflection of an object is seen in a convex mirror the image will: a. always be real. c. may be either real or virtual. b. always be virtual. d. will always be enlarged.
____ 6. Parallel rays of light that hit a concave mirror will come together: a. at the center of curvature. c. at a point half way to the focal point. b. at the focal point. d. at infinity.
____ 7. An object is placed at a distance of 50 cm from a thin lens along the axis. If a real image forms at a distance of 40 cm from the lens, on the opposite side from the object, what is the focal length of the lens? a. 22 cm c. 90 cm b. 45 cm d. 200 cm
____ 8. Which of the following effects is the result of the fact that the index of refraction of glass will vary with wavelength? a. spherical aberration c. chromatic aberration b. mirages d. light scattering
____ 9. Use of a parabolic mirror, instead of one made of a circular arc surface, can be used to reduce the occurrence of which of the following effects? a. spherical aberration c. chromatic aberration b. mirages d. light scattering
____ 10. How large should a wall-mounted mirror be to view the upper half of one’s height, h? a. h c. h/ b. h/2 d. The answer is not given.
____ 11. The real image of an object is located 45.0 cm away from a concave mirror, which has a focal length of 10. cm. How far is the object from the mirror? a. 40.0 cm c. 22.5 cm b. 35.0 cm d. 12.9 cm
____ 12. A concave mirror forms a real image at 25.0 cm from the mirror surface along the principal axis. If the corresponding object is at a 10.0-cm distance, what is the mirror’s focal length? a. 1.43 cm c. 12.4 cm b. 16.7 cm d. 7.14 cm
____ 13. If a virtual image is formed along the principal axis 10 cm from a concave mirror with the focal length 15 cm, what is the object distance from the mirror? a. 30 cm c. 12 cm b. 10 cm d. 6.0 cm
____ 14. If a virtual image is formed 10.0 cm along the principal axis from a convex mirror of focal length –15.0 cm, how far is the object from the mirror? a. 30.0 cm c. 6.00 cm b. 10.0 cm d. 3.00 cm
____ 15. A woman looking in a makeup mirror sees her face at twice its actual size and right-side up. If she is 28.0 cm from the mirror, what is its focal length? a. 18.6 cm c. 48.3 cm b. 44.0 cm d. 56.0 cm
____ 16. Which of the following best describes the image of a concave mirror when the object is at a distance greater than twice the focal point distance from the mirror? a. virtual, upright and magnification greater than one
c. virtual, upright and magnification less than one b. real, inverted and magnification less than one
d. real, inverted and magnification greater than one
____ 17. Which of the following best describes the image of a concave mirror when the object’s distance from the mirror is less than the focal point distance? a. virtual, upright and magnification greater than one
c. virtual, upright and magnification less than one b. real, inverted and magnification less than one
d. real, inverted and magnification greater than one
____ 18. Which of the following best describes the image of a convex mirror when the object’s distance from the mirror is less than the absolute value of the focal point distance? a. virtual, upright and magnification greater than one
c. virtual, upright and magnification less than one b. real, inverted and magnification less than one
d. real, inverted and magnification greater than one
____ 19. A convex mirror with focal length of 20 cm forms an image 12 cm behind the surface. Where is the object located as measured from the surface? a. 7.5 cm c. 22 cm b. 15 cm d. 30 cm
____ 20. A convex mirror with a focal length of 20 cm forms an image 15 cm behind the surface. If the object height is 1.2 cm what is the image height? a. 0.30 cm c. 0.94 cm b. 0.75 cm d. 3.0 cm
____ 30. A 3.0 cm tall object is placed along the principal axis of a thin convex lens of 30.0 cm focal length. If the object distance is 40.0 cm, which of the following best describes the image distance and height, respectively? a. 17.3 cm and 7.0 cm c. 17.3 cm and 1.3 cm b. 120 cm and 9.0 cm d. 120 cm and 1.0 cm
____ 31. Which of the following best describes the image for a thin convex lens that forms whenever the object is at a distance less than one focal length from the lens? a. inverted, enlarged and real c. upright, diminished and virtual b. upright, enlarged and virtual d. inverted, diminished and real
____ 32. An object is placed at a distance of 30 cm from a thin convex lens along its axis. The lens has a focal length of 10 cm. What are the values, respectively, of the image distance and magnification? a. 60 cm and 2.0 c. 60 cm and 0. b. 15 cm and 2.0 d. 15 cm and 0.
____ 33. Sally places an object 6.0 cm from a thin convex lens along its axis. The lens has a focal length of 9.0 cm. What are the respective values of the image distance and magnification? a. 18 cm and 3.0 c. 3.0 cm and 0. b. 18 cm and 3.0 d. 18 cm and 3.
____ 34. Ansel places an object 30 cm from a thin convex lens along the axis. If a real image forms at a distance of 10 cm from the lens, what is the focal length of the lens? a. 30 cm c. 10 cm b. 15 cm d. 7.5 cm
____ 35. Ellen places an object 40.0 cm from a concave lens. If a virtual image appears 10.0 cm from the lens on the same side as the object, what is the focal length of the lens? a. 50.0 cm c. 10.0 cm b. 13.3 cm d. 8.00 cm
____ 36. A projector lens is needed to form an image on a screen 10 times the size of its corresponding object. The screen is located 8.0 m from the lens. What is the required focal length of the lens? a. 0.32 m c. 0.73 m b. 0.54 m d. 1.25 m
____ 37. An object, located 90 cm from a concave lens, forms an image 60 cm from the lens on the same side as the object. What is the focal length of the lens? a. 36 cm c. 180 cm b. 75 cm d. 150 cm
____ 38. An object and a screen are separated by 20.00 cm. A convex lens is placed between them, 5.00 cm from the object. In this position it causes a sharp image of the object to form on the screen. What is the focal length of the lens? a. 15.0 cm c. 3.75 cm b. 5.00 cm d. 2.00 cm
____ 39. For a converging lens with two curved surfaces, the radius of curvature for both surfaces is 10 cm. If the focal length is 10 cm, what must the index of refraction be? a. 1.5 c. 2. b. 2.0 d. 3.
____ 40. For a diverging lens with one flat surface, the radius of curvature for the curved surface is 20.0 cm. What must the index of refraction be so that the focal length is 15.0 cm? a. 0.333 c. 2. b. 1.33 d. 5.
____ 41. What is the image distance of an object 1.00 m in front of a converging lens of focal length 20.0 cm? a. +16.7 cm c. +25.0 cm b. +20.0 cm d. +33.3 cm
____ 42. When an image is inverted compared to the object, it is also: a. virtual. c. enlarged. b. reversed left to right. d. diminished.
____ 43. A 100-cm focal length thin lens is placed in contact with one of 66.7 cm focal length. An object is placed 50 cm in front of the combination. What is the image distance? a. 40 cm c. 67 cm b. –25 cm d. 200 cm
____ 44. A 100-cm focal length thin lens is placed in contact with one of 66.7 cm focal length. A 3.0 cm tall object is placed 50 cm in front of the combination. What is the size of the image? a. 3.8 cm c. 4.0 cm b. 1.9 cm d. 12 cm
____ 45. Three thin lenses, each of focal length f , are placed in contact. What is the resulting focal length of the combination? a. f c. f / b. 3 f d. 3/ f
ID: A
41. C
42. B
43. D
44. D
45. C
