1. Q34.1
Which of the following changes its focal length when it is immersed in water?
1. a concave mirror
2. a convex mirror
3. a diverging lens
4. all of the above
5. none of the above

2. A34.1
Which of the following changes its focal length when it is immersed in water?
1. a concave mirror
2. a convex mirror
3. a diverging lens
4. all of the above
5. none of the above

3. Q34.2
A concave mirror with a radius of curvature of 20 cm has a focal length of
1. 40 cm
2. 20 cm
3. 10 cm
4. 5 cm
5. answer depends on the index of refraction of the air around the mirror

4. A34.2
A concave mirror with a radius of curvature of 20 cm has a focal length of
1. 40 cm
2. 20 cm
3. 10 cm
4. 5 cm
5. answer depends on the index of refraction of the air around the mirror

5. Q34.3
An object is placed 15 cm away from a concave mirror of focal length +30 cm. The image formed by the mirror is
1. real and larger than the object
2. real and smaller than the object
3. real and the same size as the object
4. virtual and larger than the object
5. virtual and smaller than the object

6. A34.3
An object is placed 15 cm away from a concave mirror of focal length +30 cm. The image formed by the mirror is
1. real and larger than the object
2. real and smaller than the object
3. real and the same size as the object
4. virtual and larger than the object
5. virtual and smaller than the object

7. Q34.4
A concave mirror forms a real image of a lamp filament.
If you use black paint to cover the lower half of the mirror, what part of the filament will be visible in the image?
1. only the upper half of the filament
2. only the lower half of the filament
3. only the left-hand half of the filament
4. only the right-hand half of the filament
5. the entire filament

8. A34.4
A concave mirror forms a real image of a lamp filament.
If you use black paint to cover the lower half of the mirror, what part of the filament will be visible in the image?
1. only the upper half of the filament
2. only the lower half of the filament
3. only the left-hand half of the filament
4. only the right-hand half of the filament
5. the entire filament

9. Q34.5
A thin 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?
1. 27 cm tall
2. 18 cm tall
3. 9 cm tall
cm tall
5. 3 cm tall

10. A34.5
A thin 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?
1. 27 cm tall
2. 18 cm tall
3. 9 cm tall
cm tall
5. 3 cm tall

11. Q34.6
Which statement is true about a farsighted (hyperopic) eye?
1. the image point is in front of the retina; a converging eyeglass lens is used to correct this condition
2. the image point is in front of the retina; a diverging eyeglass lens is used to correct this condition
3. the image point is behind the retina; a converging eyeglass lens is used to correct this condition
4. the image point is behind the retina; a diverging eyeglass lens is used to correct this condition

12. A34.6
Which statement is true about a farsighted (hyperopic) eye?
1. the image point is in front of the retina; a converging eyeglass lens is used to correct this condition
2. the image point is in front of the retina; a diverging eyeglass lens is used to correct this condition
3. the image point is behind the retina; a converging eyeglass lens is used to correct this condition
4. the image point is behind the retina; a diverging eyeglass lens is used to correct this condition

13. Q34.7
You are choosing lenses for a telescope that you will use to look at the Moon and planets. You should select
1. an objective lens with a long focal length and an eyepiece lens with an even longer focal length
2. an objective lens with a long focal length and an eyepiece lens with a shorter focal length
3. an objective lens with a short focal length and an eyepiece lens with a longer focal length
4. an objective lens with a short focal length and an eyepiece lens with an even shorter focal length

14. A34.7
You are choosing lenses for a telescope that you will use to look at the Moon and planets. You should select
1. an objective lens with a long focal length and an eyepiece lens with an even longer focal length
2. an objective lens with a long focal length and an eyepiece lens with a shorter focal length
3. an objective lens with a short focal length and an eyepiece lens with a longer focal length
4. an objective lens with a short focal length and an eyepiece lens with an even shorter focal length

15. Q34.8
You are designing a telescope that will use a single lens.
The purpose of the telescope is to take photographs of the Moon.
The linear magnification m of the image will be in the range
1. m > 1
2. 0 < m < 1
3. –1 < m < 0
4. m < –1

16. A34.8
You are designing a telescope that will use a single lens.
The purpose of the telescope is to take photographs of the Moon.
The linear magnification m of the image will be in the range
1. m > 1
2. 0 < m < 1
3. –1 < m < 0
4. m < –1