1. Q34.1
Which of the following changes its focal length when it is immersed in water?
a concave mirror
a convex mirror
a diverging lens
more than one of A, B, and C.
none of A, B, or C.
Answer: C

2. A34.1
Which of the following changes its focal length when it is immersed in water?
a concave mirror
a convex mirror
a diverging lens
more than one of A, B, and C.
none of A, B, or C.

3. Q34.2
A concave mirror with a radius of curvature of 20 cm has a focal length of
40 cm.
20 cm.
10 cm.
5 cm.
unknown, as answer depends on the index of refraction of the air around the mirror.
Answer: C

4. A34.2
A concave mirror with a radius of curvature of 20 cm has a focal length of
40 cm.
20 cm.
10 cm.
5 cm.
unknown, as answer depends on the index of refraction of the air around the mirror.

5. A. real and larger than the object.
Q34.3
An object is placed 4.0 m away from a concave mirror of focal length +1.0 m. The image formed by the mirror is
A. real and larger than the object.
B. real and smaller than the object.
C. real and the same size as the object.
D. virtual and larger than the object.
E. virtual and smaller than the object.
Answer: B

6. A34.3
An object is placed 4.0 m away from a concave mirror of focal length +1.0 m. The image formed by the mirror is
A. real and larger than the object.
B. real and smaller than the object.
C. real and the same size as the object.
D. virtual and larger than the object.
E. virtual and smaller than the object.

7. A. real and larger than the object.
Q34.4
An object is placed 2.0 m away from a concave mirror of focal length +1.0 m. The image formed by the mirror is
A. real and larger than the object.
B. real and smaller than the object.
C. real and the same size as the object.
D. virtual and larger than the object.
E. virtual and smaller than the object.
Answer: C

8. A34.4
An object is placed 2.0 m away from a concave mirror of focal length +1.0 m. The image formed by the mirror is
A. real and larger than the object.
B. real and smaller than the object.
C. real and the same size as the object.
D. virtual and larger than the object.
E. virtual and smaller than the object.

9. A. real and larger than the object.
Q34.5
An object is placed 1.5 m away from a concave mirror of focal length +1.0 m. The image formed by the mirror is
A. real and larger than the object.
B. real and smaller than the object.
C. real and the same size as the object.
D. virtual and larger than the object.
E. virtual and smaller than the object.
Answer: A

10. A34.5
An object is placed 1.5 m away from a concave mirror of focal length +1.0 m. The image formed by the mirror is
A. real and larger than the object.
B. real and smaller than the object.
C. real and the same size as the object.
D. virtual and larger than the object.
E. virtual and smaller than the object.

11. A. real and larger than the object.
Q34.6
An object is placed 0.5 m away from a concave mirror of focal length +1.0 m. The image formed by the mirror is
A. real and larger than the object.
B. real and smaller than the object.
C. real and the same size as the object.
D. virtual and larger than the object.
E. virtual and smaller than the object.
Answer: D

12. A34.6
An object is placed 0.5 m away from a concave mirror of focal length +1.0 m. The image formed by the mirror is
A. real and larger than the object.
B. real and smaller than the object.
C. real and the same size as the object.
D. virtual and larger than the object.
E. virtual and smaller than the object.

13. A. real and larger than the object.
Q34.7
An object is placed 2.0 m away from a concave mirror of focal length –1.0 m. The image formed by the mirror is
A. real and larger than the object.
B. real and smaller than the object.
C. real and the same size as the object.
D. virtual and larger than the object.
E. virtual and smaller than the object.
Answer: E

14. A34.7
An object is placed 2.0 m away from a concave mirror of focal length –1.0 m. The image formed by the mirror is
A. real and larger than the object.
B. real and smaller than the object.
C. real and the same size as the object.
D. virtual and larger than the object.
E. virtual and smaller than the object.

15. Q34.8
When you look in a cosmetics mirror of focal length f, your reflection appears right-side up and enlarged. Complete the sentence: “For a cosmetics mirror to work, the mirror must be _________ and the distance from the mirror to your face must be _________.”
Answer: B

16. A34.8
When you look in a cosmetics mirror of focal length f, your reflection appears right-side up and enlarged. Complete the sentence: “For a cosmetics mirror to work, the mirror must be _________ and the distance from the mirror to your face must be _________.”

17. A. only the object’s upper half will be visible in the image.
Q34.9
An object PQ is placed in front of a converging lens, forming a real image If you use black paint to cover the lower half of the lens,
A. only the object’s upper half will be visible in the image.
B. only the object’s lower half will be visible in the image.
C. only the object’s left-hand half will be visible in the image.
D. only the object’s right-hand half will be visible in the image.
E. the entire object will be visible in the image.
Answer: E

18. A34.9
An object PQ is placed in front of a converging lens, forming a real image If you use black paint to cover the lower half of the lens,
A. only the object’s upper half will be visible in the image.
B. only the object’s lower half will be visible in the image.
C. only the object’s left-hand half will be visible in the image.
D. only the object’s right-hand half will be visible in the image.
E. the entire object will be visible in the image.

19. Q34.10
A thin diverging lens has focal length f = –12 cm. If an object 9 cm tall is placed 24 cm from the lens, what is the height of the image?
27 cm tall
18 cm tall
9 cm tall
4.5 cm tall
3 cm tall
Answer: E

20. A34.10
A thin diverging lens has focal length f = –12 cm. If an object 9 cm tall is placed 24 cm from the lens, what is the height of the image?
27 cm tall
18 cm tall
9 cm tall
4.5 cm tall
3 cm tall

21. Which statement is true about a farsighted (hyperopic) eye?
Q34.11
Which statement is true about a farsighted (hyperopic) eye?
The image point is in front of the retina; a converging eyeglass lens is used to correct this condition.
The image point is in front of the retina; a diverging eyeglass lens is used to correct this condition.
The image point is behind the retina; a converging eyeglass lens is used to correct this condition.
The image point is behind the retina; a diverging eyeglass lens is used to correct this condition.
None of the above is true.
Answer: C

22. A34.11
Which statement is true about a farsighted (hyperopic) eye?
The image point is in front of the retina; a converging eyeglass lens is used to correct this condition.
The image point is in front of the retina; a diverging eyeglass lens is used to correct this condition.
The image point is behind the retina; a converging eyeglass lens is used to correct this condition.
The image point is behind the retina; a diverging eyeglass lens is used to correct this condition.
None of the above is true.

23. an objective lens and an eyepiece lens with equal focal lengths.
You are choosing lenses for a telescope that you will use to look at the moon and planets. You should select
an objective lens with a long focal length and an eyepiece lens with an even longer focal length.
an objective lens with a long focal length and an eyepiece lens with a shorter focal length.
an objective lens with a short focal length and an eyepiece lens with a longer focal length.
an objective lens with a short focal length and an eyepiece lens with an even shorter focal length.
an objective lens and an eyepiece lens with equal focal lengths.
Answer: B

24. A34.12
You are choosing lenses for a telescope that you will use to look at the moon and planets. You should select
an objective lens with a long focal length and an eyepiece lens with an even longer focal length.
an objective lens with a long focal length and an eyepiece lens with a shorter focal length.
an objective lens with a short focal length and an eyepiece lens with a longer focal length.
an objective lens with a short focal length and an eyepiece lens with an even shorter focal length.
an objective lens and an eyepiece lens with equal focal lengths.

25. Not enough information is given to decide.
Q34.13
You are designing a telescope that will use a single lens. The purpose of the telescope is to take photographs of the moon. The lateral magnification m of the image will be in the range
m > 1.
0 < m < 1.
–1 < m < 0.
m < –1.
Not enough information is given to decide.
Answer: C

26. A34.13
You are designing a telescope that will use a single lens. The purpose of the telescope is to take photographs of the moon. The lateral magnification m of the image will be in the range
m > 1.
0 < m < 1.
–1 < m < 0.
m < –1.
Not enough information is given to decide.

27. Object 2.0 cm from converging lens with f = +4.0 cm.
Q-RT34.1
Five identical objects, each of height 1.0 cm, are each placed on one side of one of five thin lenses. The five lenses have different focal lengths f, and the distance from the object to the lens is different in each case. Rank the five combinations of object and lens in order of the lateral magnification of the image, from most positive to most negative.
Object 2.0 cm from converging lens with f = +4.0 cm.
Object 6.0 cm from converging lens with f = +4.0 cm.
Object 4.0 cm from converging lens with f = +2.0 cm.
Object 2.0 cm from diverging lens with f = –2.0 cm.
Object 4.0 cm from diverging lens with f = –2.0 cm.
Answer: ADECB

28. A-RT34.1
Five identical objects, each of height 1.0 cm, are each placed on one side of one of five thin lenses. The five lenses have different focal lengths f, and the distance from the object to the lens is different in each case. Rank the five combinations of object and lens in order of the lateral magnification of the image, from most positive to most negative.
Object 2.0 cm from converging lens with f = +4.0 cm.
Object 6.0 cm from converging lens with f = +4.0 cm.
Object 4.0 cm from converging lens with f = +2.0 cm.
Object 2.0 cm from diverging lens with f = –2.0 cm.
Object 4.0 cm from diverging lens with f = –2.0 cm.
Answer: ADECB