Ch 17 Review Questions - Reflection and Mirrors
B09: I can apply the law of reflection.
1. Draw a picture illustrating the law of reflection, labeling relevant angles. Also, label the
incident ray and reflected ray.
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17.1: I can apply the law of reflection to a nat mirror.
17.12: I can distinguish
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between diffuse and specular reflection.
2. What is an example of a surface that has diffuse reflection? Specular? You may want to
draw diagram for yourself.
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17.2: I can distinguish
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between convex and concave mirrors.
3. Which mirror do you think is often called a "diverging mirror", th~r
the concave?
Why?
4. T or F : All incoming rays parallel to the principal axis for a concave mirror get reflected and
then pass through the focal point.
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17.3: I can identify which type of mirror corresponds to a negative or positive focal length.
5a. Explain why you could say that a convex mirror has a
of interpreting the negative sign of its focal length.
5b. What is another way of remembering/explaining
length? Think about a number line ...
why
ual" focal point. This is one way
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co vex mirror has a negative focal
17.4: I can identify whether an image for a given mirror is considered to have a positive or
negative image distance.
6. What does a negative image distance imply for a mirror? Conversely, what does a positive
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17.5: I can identify when an object has a positive or negative magnificatio
7. What does a negative magnification imply for a mirror? Conversely, what does a positive
magnification imply? .Be care~ul.not to make assum~tions and to consider all cases. Look at
your notes or draw diagrams If It helps you.
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17.6: I can identify when an object has an absolute value of magnification less than unity or
greater than unity for a mirror. (Note: "unity" is the fancy science/math word for the number 1)
8. If an image has a magnification of -4.2, what does that mean? How would that change if it
were +4.2?
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9. If an image has a magnification of -0.7, what does that mean~ ~ow would that change if it
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were +0.7?
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17.7: I can draw ray diagrams for both convex and concave mirrors.
10. Can you jot down, in your own words, 2-3 steps explaining how to do a ray diagram for
concave mirrors? Convex? Don't look at the list of steps given on the worksheet. The only
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,thing you may use is an actual ray diagram to jog your memory.
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17.8: I can label all relevant variab/~
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on a ray diagram.
17.9: I can calculate the object distance, image distance or focal length of a mirror when given
sufficient information in a problem.
17.10: I can calculate the object height or image height when given sufficient information in a
problem.
17.11: I can calculate the magnification
problem.
of a mirror when given sufficient information in a
I have a 65 mm focal lengt~ONVEX
mirror. I place an upright meter-stick 25 mm from
the mirror.
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11a. Draw a sketch of the situation using a straight-edge.
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11b. Find the image distance. Comment on its sign.
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2) The use of wav~ fronts and rays to describe optical phenomena
A wave 0 tiCS.
geometrical optiCS.
C) Isperslve op ICS.
D) quantum optics.
Answer: B
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11d. Find the image height.
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11c. Find the magnlncfation. Comment on its magnitude and sign.
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1) A laser beam strikes a plane reflecting surface with an angle of incidence of
between the incident ray and the reflected ray?
3r. What
is the angle
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Answer: 74.0°
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3) The angle of incidence can vary between zero and
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A) 1 radian.
rr/2 radians
C TT ra ians.
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E) 3TT/2 radians.
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Answer: B
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4) Law of reflection is which of the following?
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=1
C) '" (din)
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E) arc sin(nz/nl)
Answer: A
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C) specular.
Answer: A
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6) Refle
'rror is called
A) specular reflection.
C) irregular reflection.
0) internal reflection.
Answer: A
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7) The an Ie o'
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must equal the angle of reflection.
I a ways ess than the ang e of reflection.
C) may be greater than, less than, or equal to the angle of reflection.
D) is always greater than the angle of reflection.
Answer: A
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2) The IMAGE of a plane mirror (of a real object) has t8e folio
ing chara~l~ristLcs:
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A) virtual, inverted, and magnification> 1
. ua, erect and ma nllca Ion real, erect, and magnification = 1
D) real, inverted, and magnification < 1
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Answer: B
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3) David stands 2.5 meters in front of a plane mirror.
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(a ) How far f rom D'd'
aVI IS D aVI'd"s Image .In th e mirror.
(b) If David moves away from the mirror at 1.5 ml s, how fast
apart from each other?
(c) If David is 180. cm tall, how tall is his image in the mirror?
Answer: (a) 5.0 m
(b) 3.0 mls
(c) 180. cm
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are David and his image moving
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5) Suppose a lighted candle is placed a short distance from a plane mirror, as shown here.
Where will the image of the flame be located?
A) at A
M
at
~ ) at M (at the mirror)
Answer: C
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13) You may have seen ambulances on the street with the Jetters of the word AMBULANCE written
on the front of them, in such a way as to appear correctly when viewed in your car's rear-view
mirror.
a) 'I1I-lSn1'V'N:JE
How do the letters appear when you look directly at
the ambulance?
b) AMBUJAvD3
c) ECNALUBMA
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A) figure a
B) figure b
C) figure c
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Answer: E
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1) If you stand in front of a G.onvexmirror, at the same distance from it as its focal length,
you WI see your I a
WI appear smaller.
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evC) you will see your image and you will appear larger.
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D) you will see your image at your same height.
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E) you won't see your image because it's focused at a different distance.
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Answer: A
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6) The magnification M = -d;l do is the ratio of image to object
r size.
B) distance.
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D) heights.
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Answer: B
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7) A 3.0 cm tall statue is 24. cm in front of a concave mirror. The mirror radius of curvature is 20. cm.
(a) Is the image real or virtual?
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(b) How far is the image from the mirror?
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(c) Is the image upright or inverted?
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Answer: (a) real
(b) 17. cm
(c) inverted
(d) 2.1 cm
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Answer: concave mirror with focal length 15.4. cm (radius 31. cm)
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11) A negative ma nific .
e image is inverted, and the mirror is concave
e Image I
mirror IS convex.
C) the image is inverted, and the mirror may be concave or convex.
D) the image is upright, and the mirror may be concave or convex.
E) the image is upright, and the mirror is convex.
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10) Describe a mirror which takes an object at a distance of 47?1:rhh,atorms
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12) Which of the following is an accurate statement?
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A) A mirror always forms a virtual image. f'\.~ '" ~~
B) A mirror always forms a real image.
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e) A mirror always forms an image larger than the object. Y\...Ot- a.lI..v~...s
D) A m'
n image smaller than the object. t\.I to- 6-LL.'o'l1.u..s
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Answer: E
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13) Two parallel rays (also parallel to the principal axis) reflect from a concave mirror. They intersect
at
A) the center of curvature.
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C) poillt bel II
D) infinity.
Answer: B
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the mirror.
15) Sometimes when you look into a curved mirror you see a magnified image (a great big you!) and
sometimes you see a diminished image (a little you). If you look at the bottom (convex) side of a shiny
spoon, what will you see?
A) You will either see a little you or a great big you, depending on how near you are to the
spoon.
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B) Yo
u u side down.
You will see a little
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D 0 won t see an image
rself because no image will be formed. a-/W"tJJ.J,.~ V1j2..1U.I4-J.E) You will see a little you, but whether you are right side up or upside down dep~nds on how
near you are to the spoon.
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Answer: C
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19) An object is placed 6 cm from a concave mirror of radius 4 cm. Graphically determine:
(a) the image position.
(b) if the image is larger, smaller, or the same size as the object.
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(c) if the image is real or virtual.
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(b) smaller
(c) real
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21) The rear-view mirrors on the passenger side of many new cars have a Iwa~~ng written on them:
"OBJECTS IN MIRROR ARE CLOSER THAN THEY APPEAR." This implies that the mirror must be
A) concave.
B.lplane.
@convex.
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D) transparent.
Answer:
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C
23) If you stand in front of a concave mirror, exactly at its center of curvature,
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A) you will see your image and you will appear smaller.
B) you will see your image and you will appear larger.
C) you won't see your image because there is none.
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ur ima e because it's focused at a different/distance.
E) you will see your ima
r same hel
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Answer: E (you are twice the focal length away. Try the math.)
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24) If you stand in front of ~irror,
at the same distance from it as its rapius of curvature,
A) you won't see yo~b~cause
there is none.
B)you will see your image and ou will a ear lar er.
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E) you won't see your image because it's focused at a different distance. (J {~
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Answer: C
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25) An object 2.0 cm tall is placed 24. cm in front of a convex mirror whose focal length is 30. cm.
(a) Where is the image formed?
(b) How tall is it?
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Answer: (a) 14. cm behind the mirror
(b) 1.2 cm tall
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26) An object is placed 15. cm from a~
tall,
(a) where is the image formed?
(b) how tall is it?
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Answer: (a) 60. cm behind the mirror
(b) 16. cm tall
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Chapter 18 Focused Review - Refraction and Lenses
Reference Information
Index of refraction
Medium
Crown alass
Quartz
Flint alass
Diamond
Index of refraction
Medium
Vacuum
Air
Water
Ethanol
1.00000
1.0003
1.33
1.36
1.52
1.54
1.61
2.42
ROE Objectives
808. I can identify
and describe
refraction.
What causes refraction? When does is occur?
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OPRF Physics Custom Objectives
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1. I can locate angle of incidence and angle of refraction on a Snell's law "gram.
What is a "normal line" in the context of Snell's law?
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2. I can define index of refraction mathematically and explain its meaning in my own words.
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Given the speed of light in cubicblingonia is 2.5 x 108 mIs, the index of refraction
in this substance is
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3. I can predict what will happen when a ray of light traveling through a medium approache
boundary to another medium with a different index of refraction.
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Explain how a mirage occurs, making mention of refractive index, temperature,
and light rays.
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4. I can define Snell's law and use it to analyze different scenarios concerning refraction.
What is Snell's law used for? Be specific in your description and use accurate
vocabulary.
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5. I can describe total internal reflection in my own words and calculate "critical angle".
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How does a fiber optic cable work?
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6. I can define dispersion ,recognize examples of dispersion, and explain its connection with the
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concept of refraction.
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Why does dispersion happen? E~plain why different colors of light refract to
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7. I can distinguish between the shape & characteristics of a concave lens versus those of a
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convex lens.
What kind of images can concave lenses produce? Convex?
What kind of lens would you use for a magnifying glass and why? Use previous
ray diagrams if you're stuck.
8. I can interpret/comment
on the numerical value of the focal length for a concave lens and for
a convex lens.
Which lens has a positive focal length? Negative?