light and lenses
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____ 1. Which portion of the electromagnetic spectrum is used in a microscope?
a. / infrared waves / c. / visible lightb. / gamma rays / d. / ultraviolet light
____ 2. What is the frequency of infrared light of 1.0 ´ 10 m wavelength?
a. / 3.0 ´ 10 Hz / c. / 3.0 ´ 10 Hzb. / 3.0 ´ 10 Hz / d. / 3.0 ´ 10 Hz
____ 3. What is the frequency of an electromagnetic wave with a wavelength of 1.0 x 10 m?
a. / 3.3 ´ 10 Hz / c. / 1.0 ´ 10 Hzb. / 3.0 ´ 10 Hz / d. / 3.0 ´ 10 Hz
____ 4. When red light is compared with violet light,
a. / both have the same frequency. / c. / both travel at the same speed.b. / both have the same wavelength. / d. / red light travels faster than violet light.
____ 5. If a light ray strikes a flat mirror at an angle of 14° from the normal, the reflected ray will be
a. / 14° from the mirror’s surface. / c. / 90° from the mirror’s surface.b. / 76° from the normal. / d. / 14° from the normal.
____ 6. The image of an object in a flat mirror is always
a. / larger than the object. / c. / independent of the size of the object.b. / smaller than the object. / d. / the same size as the object.
____ 7. If you stand 3.0 m in front of a flat mirror, how far away from you would your image be in the mirror?
a. / 1.5 m / c. / 6.0 mb. / 3.0 m / d. / 12.0 m
____ 8. For a spherical mirror, the focal length is equal to ____ the radius of curvature of the mirror.
a. / one-fourth / c. / one-halfb. / one-third / d. / the square of
____ 9. 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. / 1.40 cm / c. / 12.0 cmb. / 7.14 cm / d. / 17.0 cm
____ 10. A convex mirror with a focal length of –20.0 cm has an object 30.0 cm in front of the mirror. What is the value of di for the corresponding image?
a. / c.b. / d.
____ 11. A mirror has an object located on its principal axis 40.0 cm from the mirror’s surface. A virtual image is formed 15.0 cm behind the mirror. What is the mirror’s focal length?
a. / c.b. / d.
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____ 12. In the diagram shown above, the image of object B would be
a. / real, reduced, and upright. / c. / virtual, reduced, and inverted.b. / virtual, enlarged, and upright. / d. / virtual, reduced, and upright.
____ 13. Which 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 oneb. / real, inverted, and magnification less than one
c. / virtual, upright, and magnification less than one
d. / real, upright, and magnification greater than one
____ 14. Which 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 oneb. / real, inverted, and magnification less than one
c. / virtual, upright, and magnification less than one
d. / real, inverted, and magnification greater than one
____ 15. Which pair of glasses shown above is best suited for automobile drivers? The transmission axes are shown by straight lines on the lenses. (Hint: The light reflects off the hood of the car.)
a. / A / c. / Cb. / B / d. / D
____ 16. If you looked at a light through the lenses from two polarizing sunglasses that were overlapped at right angles to each other,
a. / all of the light would pass through. / c. / little of the light would pass through.b. / most of the light would pass through. / d. / none of the light would pass through.
____ 17. Refraction is the bending of a wave disturbance as it passes at an angle from one ____ into another.
a. / glass / c. / areab. / medium / d. / boundary
____ 18. Which is an example of refraction?
a. / A parabolic mirror in a headlight focuses light into a beam.b. / A fish appears closer to the surface of the water than it really is when observed from a riverbank.
c. / In a mirror, when you lift your right arm, the left arm of your image is raised.
d. / Light is bent slightly around corners.
____ 19. When light passes at an angle to the normal from one material into another material in which its speed is lower (more dense),
a. / it is bent toward the normal to the surface.b. / it always lies along the normal to the surface.
c. / it is unaffected.
d. / it is bent away from the normal to the surface.
____ 20. What type of image is formed when rays of light actually intersect?
a. / real / c. / curvedb. / virtual / d. / projected
____ 21. The focal length for a converging lens is
a. / always positive.b. / always negative.
c. / dependent on the location of the object.
d. / dependent on the location of the image.
____ 22. A virtual image has a ____ image distance (q) and is located in ____ of the lens.
a. / positive, front / c. / negative, frontb. / positive, back / d. / negative, back
____ 23. The focal length for a diverging lens is
a. / always positive.b. / always negative.
c. / dependent on the location of the object.
d. / dependent on the location of the image.
____ 24. An object is placed 20.0 cm from a thin converging lens along the axis of the lens. If a real image forms behind the lens at a distance of 8.00 cm from the lens, what is the focal length of the lens?
a. / 5.71 cm / c. / –13.3 cmb. / 12.0 cm / d. / 13.3 cm
____ 25. A film projector produces a 1.51 m image of a horse on a screen. If the projector lens is 4.00 m from the screen and the size of the horse on the film is 1.07 cm, what is the magnitude of the magnification of the image?
a. / 141 / c. / 0.708b. / 14.1 / d. / 7.08 ´ 10
____ 26. An object that is 18 cm from a converging lens forms a real image 22.5 cm from the lens. What is the magnification of the image?
a. / –1.25 / c. / 0.80b. / –0.80 / d. / 1.25
____ 27. Which is not correct when describing the formation of rainbows?
a. / A rainbow is really spherical in nature.b. / Sunlight is spread into a spectrum when it enters a spherical raindrop.
c. / Sunlight is internally reflected on the back side of a raindrop.
d. / All wavelengths refract at the same angle.
Short Answer
28. What is the sign for the image distances ( di ) that is measured on the front side of any mirror which can only be a concave mirror?
29. If an image height is negative, where is the image located in relation to the principal axis?
30. An object’s distance (do) is 20.0 cm, and its image distance (di) is 10.0 cm. What is the magnification of the image?
Is the image upright or inverted?
Is the image real or virtual?
31. An object’s distance is 15.0 cm, and its image distance is 25.0 cm behind the mirror. If the height of the object is 10.0 cm, what is the height of the image?
.
32. What type of image do flat mirrors always form?
33. When does refraction occur?
.
34. What happens to the speed of light as it moves into a substance with a higher index of refraction (more dense)?
35. What is the position and kind of image produced by the lens shown above? Draw a ray diagram to support your answer.
36. Use the figure shown above to describe how a mirage is produced.
light and lenses
Answer Section
MULTIPLE CHOICE
1. ANS: C PTS: 1 DIF: I OBJ: 13-1.1
2. ANS: D
PTS: 1 DIF: IIIA OBJ: 13-1.2
3. ANS: B
PTS: 1 DIF: IIIA OBJ: 13-1.2
4. ANS: C PTS: 1 DIF: II OBJ: 13-1.3
5. ANS: D PTS: 1 DIF: II OBJ: 13-2.2
6. ANS: D PTS: 1 DIF: I OBJ: 13-2.3
7. ANS: C
PTS: 1 DIF: IIIA OBJ: 13-2.3
8. ANS: C PTS: 1 DIF: I OBJ: 13-3.1
9. ANS: B
PTS: 1 DIF: IIIB OBJ: 13-3.1
10. ANS: B
PTS: 1 DIF: IIIB OBJ: 13-3.1
11. ANS: A
PTS: 1 DIF: IIIB OBJ: 13-3.1
12. ANS: D PTS: 1 DIF: II OBJ: 13-3.3
13. ANS: B PTS: 1 DIF: II OBJ: 13-3.3
14. ANS: A PTS: 1 DIF: II OBJ: 13-3.3
15. ANS: C PTS: 1 DIF: II OBJ: 13-4.3
16. ANS: D PTS: 1 DIF: II OBJ: 13-4.3
17. ANS: B PTS: 1 DIF: I OBJ: 14-1.1
18. ANS: B PTS: 1 DIF: II OBJ: 14-1.1
19. ANS: A PTS: 1 DIF: I OBJ: 14-1.2
20. ANS: A PTS: 1 DIF: I OBJ: 14-2.1
21. ANS: A PTS: 1 DIF: I OBJ: 14-2.2
22. ANS: C PTS: 1 DIF: I OBJ: 14-2.2
23. ANS: B PTS: 1 DIF: I OBJ: 14-2.2
24. ANS: A
Given
Solution
PTS: 1 DIF: IIIA OBJ: 14-2.2
25. ANS: A
Given
Solution
PTS: 1 DIF: IIIA OBJ: 14-2.3
26. ANS: A
Given
Solution
PTS: 1 DIF: IIIA OBJ: 14-2.3
27. ANS: D PTS: 1 DIF: I OBJ: 14-3.3
SHORT ANSWER
28. ANS:
positive
PTS: 1 DIF: I OBJ: 13-3.1
29. ANS:
below the principal axis
PTS: 1 DIF: I OBJ: 13-3.1
30. ANS:
PTS: 1 DIF: IIIA OBJ: 13-3.1
31. ANS:
PTS: 1 DIF: IIIA OBJ: 13-3.1
32. ANS:
virtual
PTS: 1 DIF: I OBJ: 13-3.3
33. ANS:
Refraction occurs when light’s velocity changes as it passes from one medium to another medium with a different index of refraction.
PTS: 1 DIF: I OBJ: 14-1.1
34. ANS:
The speed of light decreases. or bends toward the normal
PTS: 1 DIF: I OBJ: 14-1.1
35. ANS:
A real, inverted image that is larger than the object will form outside 2F.
PTS: 1 DIF: II OBJ: 14-2.1
36. ANS:
In this situation, the observer sees the palm tree in two different ways. One group of light rays reaches the observer by the straight-line path A. In addition, a second group of rays travels along the curved path B because of refraction. Consequently, the observer also sees an inverted image of the palm tree.
PTS: 1 DIF: I OBJ: 14-3.2