Deck 23: Mirrors and Lenses

Question 1

Suppose you place an object in front of a concave mirror.Which of the following statements must be true? (There could be more than one correct choice.)

A)The image of the object will always be smaller than the object.
B)No matter where you place the object, a real image of the object will be formed.
C)The image of the object will always be inverted.
D)If you position the object between the mirror and the focal point of the mirror, its image must be upright and virtual.
E)No matter where you place the object, the image of the object will always be virtual and upright.

Answer 1

D

Question 2

An object is placed to the left of a spherical mirror in front of the mirror.If the image of the object is formed on the right side of the mirror,which of the following statements must be true? (There could be more than one correct choice.)

A)The image is upright and the mirror must be convex.
B)The image is inverted and real, and the mirror must be convex.
C)The image is upright and the mirror must be concave.
D)The image is upright and virtual.
E)The mirror could be either concave or convex.

Answer 2

D,E

Question 3

If a spherical convex mirror has a radius of curvature R,the magnitude of its focal length is

A)R/2.
B)R/4.
C)R.
D)2R.
E)4R.

Answer 3

A

Question 4

A convex mirror has a focal length of magnitude f.An object is placed in front of this mirror at a point f from the face of the mirror.The image will appear

A)behind the mirror.
B)upright and reduced.
C)upright and enlarged.
D)inverted and reduced.
E)inverted and enlarged.

Question 5

You may have seen ambulances on the street with the letters 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.(See the figure.)How do the letters appear when you look directly at the ambulance (not through the mirror)?

A)a
B)b
C)c
D)d
E)e

Question 6

The image formed in a plane mirror is

A)at the same distance in front of the mirror as the object is in front of the mirror.
B)a real image behind the mirror.
C)at the same distance behind the mirror as the object is in front of the mirror.
D)at a shorter distance behind the mirror than the distance the object is in front of the mirror.
E)at a larger distance behind the mirror than the distance the object is in front of the mirror.

Question 7

As you walk away from a plane mirror on a wall,the height of your image

A)gets smaller.
B)may or may not get smaller, depending on where the observer is positioned.
C)is always a real image, no matter how far you are from the mirror.
D)changes from being a virtual image to a real image as you pass the focal point.
E)is always the same size.

Question 8

If an object is placed at the center of curvature of concave mirror,the image formed by the mirror is located

A)out beyond the center of curvature.
B)at the center of curvature.
C)between the center of curvature and the focal point.
D)at the focal point.
E)at infinity.

Question 9

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 won't see an image of yourself because no image will be formed.
B)You will see a little you, upside down.
C)You will see a little you, right side up.
D)You will see a little you, but whether you are right side up or upside down depends on how near you are to the spoon.
E)You will either see a little you or a great big you, depending on how near you are to the spoon.

Question 10

If you stand in front of a convex mirror,at the same distance from it as its focal length,

A)you won't see your image because there is none.
B)you won't see your image because it is focused at infinity.
C)you will see your image and you will appear smaller than you.
D)you will see your image and you will appear larger than you.
E)you will see your image and it will be the same size as you except upside down.

Question 11

Which of the following statements about spherical mirrors is correct? (There could be more than one correct choice.)

A)A concave mirror always produces a real image.
B)A convex mirror always produces a virtual image.
C)A concave mirror always produces a virtual image.
D)A convex mirror always produces a real image.
E)A convex mirror always produces an upright image.

Question 12

If you stand in front of a convex mirror,at the same distance from it as its radius of curvature,

A)you won't see your image because there is none.
B)you won't see your image because it is focused at infinity.
C)you will see your image and you will appear smaller than you.
D)you will see your image and you will appear larger than you.
E)you will see your image and it will be the same size as you except upside down.

Question 13

Which statements about images are correct? (There could be more than one correct choice.)

A)A virtual image cannot be formed on a screen.
B)A virtual image cannot be viewed by the unaided eye.
C)A virtual image cannot be photographed.
D)A real image must be erect.
E)Mirrors always produce real images because they reflect light.

Question 14

Which one of the following numbers is the correct magnification produced by a plane mirror?

A)1/2
B)1/4
C)2
D)1
E)3/2

Question 15

Which one of the following sets of characteristics describes the image formed by a plane mirror?

A)real and inverted
B)real and upright
C)virtual and upright
D)virtual and inverted
E)virtual and larger than the object

Question 16

An object is placed in front of a convex mirror at a distance larger than twice the magnitude of the focal length of the mirror.The image will appear

A)in front of the mirror.
B)inverted and reduced.
C)inverted and enlarged.
D)upright and reduced.
E)upright and enlarged.

Question 17

If a spherical concave mirror has a radius of curvature R,its focal length is

A)R/4.
B)R/2.
C)R.
D)2R.
E)4R.

Question 18

The focal length of a concave mirror has a magnitude of 20 cm.What is its radius of curvature?

A)10 cm
B)40 cm
C)-40 cm
D)20 cm
E)-20 cm

Question 19

A lighted candle is placed a short distance from a plane mirror,as shown in the figure.At which location will the image of the flame appear to be located?

A)at A
B)at B
C)at C
D)at M (at the mirror)

Question 20

The focal length of a convex mirror is has a magnitude of 20 cm.What is its radius of curvature?

A)-10 cm
B)40 cm
C)-40 cm
D)-20 cm
E)20 cm

Question 21

A beam of light that is parallel to the principal axis strikes a concave mirror.What happens to the reflected beam of light?

A)It also is parallel to the principal axis.
B)It is perpendicular to the principal axis.
C)It passes through the center of curvature of the mirror.
D)It passes through the focal point of the mirror.
E)It passes between the focal point and the center of curvature of the mirror.

Question 22

A convex lens has focal length f.If an object is located at "infinity" (very far away),the image formed is located at a distance from the lens

A)of 2f.
B)between f and 2f.
C)of f.
D)between the lens and f.
E)of infinity.

Question 23

Single convex spherical mirrors produce images that

A)are always smaller than the actual object.
B)are always larger than the actual object.
C)are always the same size as the actual object.
D)could be larger than, smaller than, or the same size as the actual object, depending on the placement of the object.
E)are sometimes real.

Question 24

A convex lens has focal length f.If an object is placed at a distance between f and 2f from the lens on the principal axis,the image is located at a distance from the lens

A)of 2f.
B)between f and 2f.
C)of f.
D)that is greater than 2f.
E)of infinity.

Question 25

Which of following statements about the image formed by a single concave lens are true? (There could be more than one correct choice.)

A)The image is always real.
B)The image is always virtual.
C)The image is always inverted.
D)The image is always upright.
E)The image is always smaller than the object.

Question 26

Which of following statements about the image formed by a single convex lens are true? (There could be more than one correct choice.)

A)The image is always real.
B)The image is always virtual.
C)The image is always inverted.
D)The image is always upright.
E)None of the above choices are correct.

Question 27

Suppose you wanted to start a fire using a mirror to focus sunlight.Which of the following statements is most accurate?

A)It would be best to use a plane mirror.
B)It would be best to use a convex mirror.
C)It would be best to use a concave mirror, with the object to be ignited positioned at the center of curvature of the mirror.
D)It would be best to use a concave mirror, with the object to be ignited positioned halfway between the mirror and its center of curvature.
E)One cannot start a fire using a mirror, since mirrors form only virtual images.

Question 28

Single concave spherical mirrors produce images that

A)are always smaller than the actual object.
B)are always larger than the actual object.
C)are always the same size as the actual object.
D)could be smaller than, larger than, or the same size as the actual object, depending on the placement of the object.
E)are always real.

Question 29

An object is placed on the left side of a thin lens,and the image of this object is formed on the left side of the lens.Which of the following statements must be true? (There could be more than one correct choice.)

A)The lens must be a concave lens, and the image is upright.
B)The lens must be a convex lens, and the image is upright.
C)The image is upright and virtual.
D)The lens could be either a convex or a concave lens, and the image is upright.
E)The image is inverted and real.

Question 30

A convex lens has focal length f.If an object is placed at a distance beyond 2f from the lens on the principal axis,the image is located at a distance from the lens

A)of 2f.
B)between f and 2f.
C)of f.
D)between the lens and f.
E)of infinity.

Question 31

A beam of light that is parallel to the principal axis strikes a convex mirror.What happens to the reflected beam of light?

A)It also is parallel to the principal axis.
B)It is perpendicular to the principal axis.
C)It appears to be coming from the focal point on the other side of the mirror.
D)It appears to be coming from the center of curvature of the mirror.
E)It appears to be coming from a point between the focal point and the center of curvature of the mirror.

Question 32

An upright object is 50 cm from a concave mirror of radius 60 cm.The character of the image is

A)real and upright
B)real and inverted
C)virtual and upright
D)virtual and inverted

Question 33

Starting from very far away,an object is moved closer and closer to a convex lens,eventually reaching the lens.What happens to its image formed by that lens? (There could be more than one correct choice.)

A)The image gets closer and closer to the lens.
B)The image gets farther and farther from the lens.
C)The image eventually changes from virtual to real.
D)The image eventually changes from real to virtual.
E)The image keeps getting larger and larger.

Question 34

Which statement about a single thin lens is correct?

A)A convex lens always produces a real inverted image.
B)A concave lens always produces a virtual inverted image.
C)A convex lens sometimes produces a real upright image.
D)A concave lens always produces a virtual upright image.
E)A concave lens produces a virtual upright image only if the object is located between the lens and its focal point.

Question 35

If a object is placed between a convex lens and its focal point,the image formed is

A)virtual and upright.
B)virtual and inverted.
C)real and upright.
D)real and inverted.

Question 36

If a single lens forms a virtual image of an object,then

A)the lens must be a concave lens.
B)the lens must be a convex lens.
C)the lens could be either a concave or a convex lens.
D)the image must be inverted.
E)the object must be between the lens and its focal point.

Question 37

Is it possible to see a virtual image?

A)No, since the rays that seem to emanate from a virtual image do not in fact emanate from the image.
B)No, since virtual images do not really exist.
C)Yes because the rays that appear to come from a virtual image can be focused by the eye just like those from an object.
D)Yes, but only by using an additional lens to form a real image before the light reaches the eye.

Question 38

Starting from very far away,an object is moved closer and closer to a concave lens,eventually reaching the lens.What happens to its image formed by that lens? (There could be more than one correct choice.)

A)The image gets closer and closer to the lens.
B)The image gets farther and farther from the lens.
C)The image always remains virtual.
D)The image eventually changes from real to virtual.
E)The image keeps getting larger and larger.

Question 39

An object is placed in front of a thin lens.Which statements are correct in describing the image formed by the lens? (There could be more than one correct choice.)

A)If the lens is convex, the image will never be virtual.
B)If the image is real, then it is also inverted.
C)If the image is real, then it is also upright.
D)If the lens is concave, the image must be virtual.
E)If the lens is convex, the image must be real.

Question 40

A convex lens has focal length f.If an object is placed at a distance of 2f from the lens on the principal axis,the image is located at a distance from the lens

A)of 2f.
B)between f and 2f.
C)of f.
D)between the lens and f.
E)of infinity.

Question 41

To maximize the magnification of a refracting telescope,what lenses should you choose?

A)The objective lens and eyepiece should both have small focal lengths.
B)The objective lens and eyepiece should both have large focal lengths.
C)The objective lens should have a small focal length and the eyepiece should have a large focal length.
D)The objective lens should have a large focal length and the eyepiece should have a small focal length.
E)The objective lens should have a large focal length, but it doesn't matter what the focal length of the eyepiece is.

Question 42

You have a choice between two lenses of focal lengths f_a and f_b,where f_b = 2f_a,to use as the objective lens in building a compound microscope.If the magnification you obtain using lens a is M_a,what will be the magnification when using lens b?

A)M_b = 2 M_a
B)M_b = 4 M_a
C)M_b = 8 M_a
D)M_b = M_a/4
E)M_b = M_a/2

Question 43

The focal length of the lens of a simple digital camera is 40 mm,and it is originally focused on a person 25 m away.In what direction must the lens be moved to change the focus of the camera to a person 4.0 m away?

A)It does not make any difference.
B)sideways from the CCD sensors
C)away from the CCD sensors
D)towards the CCD sensors

Question 44

Which one of the following is normally not a characteristic of a simple two-lens refracting astronomical telescope?

A)The angular size of the final image is larger than that of the object.
B)The final image is virtual.
C)The objective forms a virtual image.
D)The final image is inverted.

Question 45

In a compound microscope

A)both the objective and the eyepiece form real images.
B)magnification is provided by the objective lens and not by the eyepiece. The eyepiece merely increases the resolution of the image viewed.
C)magnification is provided by the objective and not by the eyepiece. The eyepiece merely increases the brightness of the image viewed.
D)the magnification is m₁ + M₂, where m₁ is the lateral magnification of the objective and M₂ is the angular magnification of the eyepiece.
E)the image of the objective serves as the object for the eyepiece.

Question 46

Farsightedness can usually be corrected with

A)convex lenses.
B)concave lenses.
C)convex mirrors.
D)cylindrical lenses.
E)concave mirrors.

Question 47

You are given two converging lenses to build a compound microscope.Lens A has focal length 0.50 cm and lens B has focal length of 3.0 cm.Which one of the two lenses would you use for the objective?

A)Lens A, because it has the shorter focal length.
B)Lens B, because it has the longer focal length.
C)It makes no difference which lens I use for the objective.
D)None, because the objective should be a diverging lens.

Question 48

Which one of the following statements is correct?

A)The image formed by the objective of a microscope is smaller than the object.
B)The image formed by the objective lens of a telescope is larger than the object.
C)The image formed by the eyepiece is real for both a microscope and a telescope.
D)The image formed by the objective lens of a microscope is larger than the object.

Question 49

A simple compound microscope normally uses

A)a short focal length objective and a shorter focal length eyepiece.
B)a short focal length objective and a longer focal length eyepiece.
C)a long focal length objective and a shorter focal length eyepiece.
D)a very long focal length objective and a longer focal length eyepiece.

Question 50

The closest object that a typical young person with normal vision can see clearly is closest to

A)1 cm.
B)10 cm.
C)25 cm.
D)50 cm.
E)75 cm.

Question 51

What type of lens is used to make a magnifying glass?

A)convex
B)concave
C)Either type would work equally well.

Question 52

Nearsightedness is usually corrected with

A)convex lenses.
B)concave lenses.
C)convex mirrors.
D)cylindrical lenses.
E)concave mirrors.

Question 53

A simple refracting telescope provides large magnification by employing

A)a short focal length objective and a short focal length eyepiece.
B)a short focal length objective and a long focal length eyepiece.
C)a long focal length objective and a short focal length eyepiece.
D)a long focal length objective and a long focal length eyepiece.

Question 54

Which one of the following is a characteristic of a compound microscope?

A)The objective is a concave lens.
B)The eyepiece is a concave lens.
C)The final image is real.
D)The image formed by the objective is virtual.
E)The image formed by the objective is real.

Question 55

For relaxed viewing with a microscope or a telescope,the eyepiece is adjusted to place the image at

A)the near point of the eye.
B)the pupil of the eye.
C)the focal point of the eyepiece.
D)infinity.
E)the focal point of the objective lens.

Question 56

If the lens in a person's eye is too highly curved,this person is suffering from

A)farsightedness.
B)spherical aberration.
C)astigmatism.
D)chromatic aberration.
E)nearsightedness.

Question 57

Jack and Mary view the same microorganism through the same compound microscope.Mary's near point distance,N_M,is twice as large as Jack's near point distance,N_J.If Mary sees the microorganism with magnification M_M,with what magnification does Jack see it?

A)2 M_M
B)M_M/2
C)4 M_M
D)M_M/4
E)8 M_M

Question 58

The image formed by a single concave lens

A)is always real.
B)is always virtual.
C)could be real or virtual, depending on whether the object distance is smaller or greater than the focal length.
D)could be real or virtual, but is always real when the object is placed at the focal point.
E)is always inverted.

Question 59

A little known fact is that both Robinson Crusoe and Friday wore eyeglasses.As it so happens,Robinson Crusoe was farsighted while Friday was nearsighted.Whose eyeglasses did they use whenever they wanted to start a fire by focusing the sun's rays?

A)Robinson Crusoe's
B)Friday's
C)Both would work equally well.
D)Both actually worked, but Friday's was a little bit better.
E)Neither's worked, but fortunately they were in possession of matches.

Question 60

If the back of a person's eye is too close to the lens,this person is suffering from

A)nearsightedness.
B)spherical aberration.
C)astigmatism.
D)chromatic aberration.
E)farsightedness.

Question 61

A stature that is 3.0 cm tall statue is 24 cm in front of a concave mirror.The magnitude of the radius of curvature of the mirror is 20 cm.
(a)Is the image real or virtual?
(b)How far is the image from the mirror?
(c)Is the image upright or inverted?
(d)How tall is the image?

Question 62

An object that is 10.0 cm tall is placed 37.0 cm in front of a concave mirror of focal length 18.5 cm.How tall is the image?

A)2.5 cm
B)5.0 cm
C)7.5 cm
D)20.0 cm
E)10.0 cm

Question 63

An object that is 4.00 cm tall is placed 18.0 cm in front of a concave mirror having a focal length of 20.0 cm.What is the location of its image in relation to the mirror and what are its characteristics?

A)180 cm on the other side of mirror, real, 6.00 times bigger
B)10 cm on the other side of mirror, virtual, 10.0 times bigger
C)18 cm on the same side of mirror, virtual, 2.25 times bigger
D)20 cm on the same side of mirror, real, 10.0 times bigger
E)180 cm on the other side of mirror, virtual, 10.0 times bigger

Question 64

An object is placed 50 cm in front of a concave mirror with a focal length of 25 cm.What is the magnification produced by the mirror?

A)-0.50
B)-1.0
C)+1.5
D)-2.0
E)+1.0

Question 65

A concave mirror having a focal length of magnitude 5.0 cm forms an image 4.0 cm behind the mirror.Where is the object for this image?

A)2.2 cm in front of the mirror
B)2.2 cm behind the mirror
C)9.0 cm in front of the mirror
D)1.0 cm behind the mirror
E)20 cm behind the mirror

Question 66

An object that is 2.0 cm tall is placed at the center of curvature in front of a concave mirror.How tall is its image?

A)0.50 cm
B)1.0 cm
C)1.5 cm
D)2.0 cm
E)infinite

Question 67

Two plane mirrors make an angle of with each other.A light ray enters the system and is reflected once off of each mirror.Through what angle is the ray turned?

A)60°
B)90°
C)120°
D)150°

Question 68

A statue that is 2.3 cm tall is placed 15 cm in front of a convex mirror.The magnitude of the radius of curvature of the mirror is 18 cm.
(a)Is the image real or virtual?
(b)How far is the image from the mirror?
(c)Is the image upright or inverted?
(d)How tall is the image?

Question 69

You have a choice between two lenses of focal lengths f_a and f_b,where f_b = 2f_a,to use as the objective lens in building a refracting telescope.If the magnification you obtain using lens a is M_a,what will be the magnification when using lens b?

A)M_b = 2 M_a
B)M_b = 4 M_a
C)M_b = 8 M_a
D)M_b = M_a/4
E)M_b = M_a/2

Question 70

Tan's face is 20 cm in front of a concave shaving mirror.If he observes his image to be twice as big and upright,what is the focal length of the mirror?

A)10 cm
B)-40 cm
C)-50 cm
D)40 cm
E)50 cm

Question 71

David stands 2.5 m in front of a plane mirror.
(a)How far from David is his image in the mirror?
(b)If David moves away from the mirror at 1.5 m/s,how fast are David and his image moving apart from each other?
(c)If David is 180 cm tall,how tall is his image in the mirror?

Question 72

A laser beam strikes a plane mirror's reflecting surface with an angle of incidence of 43°.What is the angle between the incident ray and the reflected ray?

A)43°
B)86°
C)45°
D)90°
E)0°

Question 73

An object that is 3.4 mm tall is placed 25 cm from the vertex of a convex spherical mirror.The radius of curvature of the mirror has magnitude 73 cm.
(a)How far is the image from the vertex of the mirror?
(b)What is the height of the image?

Question 74

An object that is 75 cm tall is located 3.8 m in front of a plane mirror.The image formed by the mirror appears to be

A)1.9 m in front of the mirror.
B)on the mirror's surface.
C)1.9 m behind the mirror's surface.
D)3.8 m in front of the mirror.
E)3.8 m behind the mirror's surface.

Question 75

A person jogs toward a plane mirror at a speed of 3 m/s.How fast is he approaching his image in the mirror?

A)1 5 m/s
B)3 m/s
C)4 m/s
D)5 m/s
E)6 m/s

Question 76

An object 2.0 cm tall is placed 24 cm in front of a convex mirror having a focal length of magnitude 30 cm.
(a)Where is the image formed and how far is it from the mirror?
(b)How tall is the image?

Question 77

A refracting telescope has a magnification M.If the focal length of the objective lens is doubled and the eyepiece focal length is halved,what is the new magnification?

A)4M
B)2M
C)M/2
D)M/4
E)M

Question 78

When an object is 12 cm in front of a concave mirror,the image is 3.0 cm in front of the mirror? What is the focal length of the mirror?

A)-0.25 cm
B)15 cm
C)4.0 cm
D)2.4 cm
E)-1.3 cm

Question 79

Reza's face is 20 cm in front of a concave shaving mirror having a focal length of magnitude 30 cm.How large is the image of his face?

A)half as large as his face
B)of the same size as his face
C)twice as large as his face
D)three times as large as his face
E)four times as large as his face

Question 80

An object that is 4.0 cm tall is placed 15 cm in front of a concave mirror of focal length 20 cm.
(a)Where is the image formed and how far is it from the mirror?
(b)How tall is the image?