Deck 24: Optical Instruments

Question 1

A 50.0 mm lens is used to take a picture of an object 1.30 m tall located 4.00 m away.What is the height of the image on the film?

A) 21.0 mm
B) 16.5 mm
C) 12.0 mm
D) 10.5 mm
E) 9.20 mm

Answer 1

16.5 mm

Question 2

Two lenses,the first with focal length -12.5 cm and the second with focal length 20.0 cm,are separated by 15.0 cm.If an object is place 50.0 cm in front of the first lens,where is the final image formed?

A) 10.0 cm before the first lens
B) 25.0 cm before the second lens
C) 25.0 cm after the second lens
D) 50.0 cm after the second lens
E) 100 cm after the second lens

Answer 2

100 cm after the second lens

Question 3

Two converging lenses,the first with focal length 40 cm and the second with focal length 33¹/₃ cm,are separated by 10.0 cm.An object of height 6.0 cm is placed 20.0 cm in front of the first lens.What are the size and orientation of the final image?

A) 6.0 cm,upright
B) 6.0 cm,inverted
C) 24 cm,upright
D) 24 cm,inverted
E) 1.5 cm,inverted

Answer 3

24 cm,inverted

Question 4

Two lenses,the first with focal length 10.0 cm and the second with focal length -12.5 cm,are separated by 20.0 cm.An object,2.40 cm tall,is 15.0 cm in front of the first lens.Where is the final image?

A) 20.0 cm after the second lens
B) 12.5 cm after the second lens
C) 5.60 cm after the second lens
D) 50.0 cm after the second lens
E) 100 cm after the second lens

Question 5

Two converging lenses,the first with focal length 40 cm and the second with focal length 33¹/₃ cm,are separated by 10.0 cm.An object of height 6.0 cm is placed 20.0 cm in front of the first lens.Where is the final image formed?

A) 10 cm before the first lens
B) 50 cm before the first lens
C) 50 cm after the second lens
D) 100 cm after the second lens
E) 33¹/₃ cm after the second lens

Question 6

The lens of a slide projector has a focal length of 10.0 cm.It is used to project the image of a 35 mm slide (24 mm $\times$ 36 mm)on a square screen located 6.0 m away.Of the following screen widths,which is the smallest that would allow the image to fit?

A) 5.1 m
B) 4.4 m
C) 2.2 m
D) 1.1 m
E) 0.88 m

Question 7

The image area on 35 mm film is 24 mm $\times$ 36 mm.What focal length lens of the following will allow an image of the moon,0.50 $^{\circ}$ in diameter,to just fit on the film?

A) 2.8 m
B) 1.4 m
C) 0.85 m
D) 12 mm
E) 55 mm

Question 8

Two converging lenses,the first with focal length 10.0 cm and the second with focal length 20.0 cm,are separated by 40.0 cm.An object,3.00 cm in height,is placed 30.0 cm in front of the first lens.What is the height of the final image?

A) 3.00 cm
B) 1.50 cm
C) 6.00 cm
D) 12.0 cm
E) 24.0 cm

Question 9

Two converging lenses,the first with focal length 25 cm and the second with focal length 20 cm,are separated by 30 cm.A 4.0 cm tall object is placed 50 cm in front of the first lens.What is the height of the final image?

A) 4.0 cm
B) 2.0 cm
C) 8.0 cm
D) 9.3 cm
E) 1.0 cm

Question 10

Two converging lenses,the first with focal length 10.0 cm and the second with focal length 20.0 cm,are separated by 40.0 cm.An object,3.00 cm in height,is placed 30.0 cm in front of the first lens.Where is the image caused by the first lens?

A) 7.50 cm after the first lens
B) 7.50 cm after the second lens
C) 15.0 cm after the first lens
D) 15.0 cm after the second lens
E) 55.0 cm after the second lens

Question 11

Two lenses,the first with focal length -12.5 cm and the second with focal length 20.0 cm,are separated by 15.0 cm.If an object is place 50.0 cm in front of the first lens,what is the total magnification?

A) 20.0
B) -20.0
C) 1.25
D) -1.25
E) -0.800

Question 12

Two lenses,the first with focal length 10.0 cm and the second with focal length -12.5 cm,are separated by 20.0 cm.An object,2.40 cm tall,is 15.0 cm in front of the first lens.What is the size of the final image?

A) 2.40 cm
B) 4.80 cm
C) 12.4 cm
D) 24.0 cm
E) 0.96 cm

Question 13

Two lenses,the first with focal length 10.0 cm and the second with focal length -12.5 cm,are separated by 20.0 cm.An object,2.40 cm tall,is 15.0 cm in front of the first lens.Which of the following characteristics does the final image have?

A) real and upright
B) real and inverted
C) virtual and upright
D) virtual and inverted
E) virtual and diminished in size

Question 14

A 10 D lens is placed in contact with a 15 D lens.What is the refractive power of the combination?

A) 15 D
B) 25 D
C) 0.67 D
D) 5.0 D
E) 1.5 D

Question 15

Two converging lenses,the first with focal length 10.0 cm and the second with focal length 20.0 cm,are separated by 40.0 cm.An object,3.00 cm in height,is placed 30.0 cm in front of the first lens.Where is the final image formed?

A) 11.1 cm after the second lens
B) 100 cm after the second lens
C) 45.0 cm after the second lens
D) 5.00 cm after the second lens
E) 5.00 cm before the second lens

Question 16

A lens of focal length 1500 mm is used to project an in image of the sun.If the sun subtends an angle of 0.50 $^{\circ}$ ,what is the diameter of the image?

A) 60 mm
B) 30 mm
C) 26 mm
D) 6.5 mm
E) 13 mm

Question 17

Two converging lenses,the first with focal length 25 cm and the second with focal length 20 cm,are separated by 30 cm.A 4.0 cm tall object is placed 50 cm in front of the first lens.Where is the final image?

A) 20 cm after the second lens
B) 20 cm before the second lens
C) 10 cm after the second lens
D) 10 cm before the second lens
E) 50 cm after the second lens

Question 18

Two converging lenses,the first with focal length 10.0 cm and the second with focal length 20.0 cm,are separated by 40.0 cm.An object,3.00 cm in height,is placed 30.0 cm in front of the first lens.Which of the following characteristics does the final image have?

A) real and upright
B) real and inverted
C) virtual and upright
D) virtual and inverted
E) none of these choices are correct

Question 19

Two converging lenses,the first with focal length 25 cm and the second with focal length 20 cm,are separated by 30 cm.A 4.0 cm tall object is placed 50 cm in front of the first lens.Where is the image caused by the first lens? Give the most inclusive answer.

A) 50 cm after the first lens
B) 20 cm after the second lens
C) both 50 cm after the first lens and 20 cm after the second lens
D) 50 cm after the second lens
E) 20 cm before the second lens

Question 20

Two converging lenses,the first with focal length 25 cm and the second with focal length 20 cm,are separated by 30 cm.A 4.0 cm tall object is placed 50 cm in front of the first lens.Which of the following characteristics does the final image have?

A) real and upright
B) real and inverted
C) virtual and upright
D) virtual and inverted
E) none of these choices are correct

Question 21

Of the following distances,which is the closest an object can be to a lens of focal length f and still give a real image?

A) 3f
B) 2f
C) 1.2f
D) 0.8f
E) 0.49f

Question 22

If an object is placed before a singe thin lens

A) real images are always enlarged.
B) virtual images are always inverted.
C) real images are always inverted.
D) convex lenses never create virtual images.

Question 23

A lens of focal length 10 cm is placed in contact with a lens of focal length -15 cm.What is the focal length of the combination?

A) -15 cm
B) 6.0 cm
C) 7.5 cm
D) -5.0 cm
E) 30 cm

Question 24

A camera with a 50.0 mm lens is designed to focus from 1.00 m to infinity.What is the distance of travel of the lens with respect to the film plane over this range of focus?

A) 50.0 mm
B) 52.6 mm
C) 47.4 mm
D) 5.30 mm
E) 2.60 mm

Question 25

For maximum angular magnification of a compound microscope,the objective focal length (f_o)and the eyepiece focal length (f_e)should be chosen so that

A) f_o and f_e are the largest available.
B) f_o and f_e are the smallest available.
C) f_o is the smallest available -f_e is the smallest available.
D) f_o is the largest available -f_e is the smallest available.

Question 26

The loss of accommodation that comes with aging is called

A) myopia.
B) hyperopia.
C) presbyopia.
D) retinalopia.
E) macularopia.

Question 27

A lens has a refractive power of -1.50.What is its focal length?

A) 150 cm
B) -150 cm
C) 67.0 cm
D) -67.0 cm
E) 8.50 cm

Question 28

The two lenses in a compound microscope work by

A) both forming virtual images.
B) the lens closest to the object forming a real image,and the other lens forms a virtual image.
C) both forming real images.
D) the lens closest to the object forming a virtual image,and the other lens forms real image.

Question 29

Decreasing the focal length of the eyepiece in a compound microscope by 50% changes the magnification to _______ times the previous magnification.

A) 0.50
B) 1.5
C) 1.7
D) 2.0
E) 4.0

Question 30

What magnifying power is attained using a compound microscope with the following specifications: objective focal length 1.50 cm,eyepiece focal length 2.42 cm,tube length 16.0 cm? Assume a near point of 25.0 cm and that the microscope is adjusted for an image at infinity.

A) 110
B) 90.0
C) 12.0
D) 11.0
E) 8.00

Question 31

To get the same exposure on the film,when the aperture diameter of a camera lens is doubled,what change should be made in the shutter speed?

A) it should be doubled
B) it should be halved
C) it should be quadrupled
D) it should be quartered
E) it should be reduced by a factor of 1.414

Question 32

A small object has an angular diameter of 0.50 $^{\circ}$ .When viewed through a magnifier,it has an angular diameter of 8.0 $^{\circ}$ .What is the angular magnification in this case?

A) 4.0
B) 8.0
C) 16
D) 32
E) 8.5

Question 33

A farsighted person cannot see clearly closer than 2.0 m.What power contact lenses would correct this near point to 25 cm?

A) 2.0 D
B) 0.5 D
C) -0.5 D
D) 3.5 D
E) -3.5 D

Question 34

Increasing the aperture on a camera

A) reduces the depth of field and requires a longer exposure time.
B) reduces the depth of field and requires a shorter exposure time.
C) increases the depth of field and requires a longer exposure time.
D) increases the depth of field and requires a shorter exposure time.

Question 35

The eye focuses by

A) moving the lens.
B) moving the retina.
C) moving both the lens and the retina.
D) changing the focal length of the lens.
E) changing the index of refraction of the vitreous fluid.

Question 36

A concave mirror has a radius of 2.0 m.What is the refractive power of a lens of the same focal length as the mirror?

A) 0.50 D
B) 1.0 D
C) 2.0 D
D) 0.75 D
E) -0.50 D

Question 37

A nearsighted person has a far point of 33 cm.What focal length contact lens would allow her to see in the distance?

A) 33 cm
B) -33 cm
C) 67 cm
D) -67 cm
E) 3.0 m

Question 38

Three lenses,each of focal length 90 cm,are placed in contact.What is the focal length of the combination?

A) 27 cm
B) 93 cm
C) 1/30 cm
D) 45 cm
E) 30 cm

Question 39

A 5.0 cm focal length lens is used as a magnifier.Assuming a near point of 25 cm,about what magnification is attained?

A) 25
B) 10
C) 60
D) 1.2
E) no value given is within 2 of an appropriate answer

Question 40

A camera with changeable lenses produces an image of an object that is 3.0 mm wide on the film when the 50.0 mm lens is used.When the 135 mm lens is used,how wide is the image of the object on the film?

A) 3.0 mm
B) 85 mm
C) 4.5 mm
D) 0.37 mm
E) 8.1 mm

Question 41

A compound microscope has three possible objective lenses and two eyepiece lenses For maximum angular magnification,the objective (f₀)and eyepiece (fe)should be chosen such that

A) f₀ and fe are both the largest available.
B) f₀ and fe are both the smallest available.
C) f₀ is the largest available: fe is the smallest available.
D) f₀ is the is the smallest available: fe is the largest available.

Question 42

A pinhole camera is used to produce an image of a bird that is 3.8 m from the pinhole,onto the projection screen.If the size of the bird's image is 3.0% of the size of the bird,what is the distance from pinhole to screen?

A) 5.7 cm
B) 23 cm
C) 11 cm
D) impossible to determine given the information.

Question 43

How is chromatic aberration corrected in large astronomical reflecting telescopes?

A) a combination of lenses designed to cancel the aberrations
B) use a parabolic mirror instead of a spherical mirror
C) a properly constructed telescope has no aberration
D) change the resolution of the telescope

Question 44

Which statement best explains why we are able to see details of a distant object more clearly?

A) the image formed by the telescope is larger than the object
B) the image formed by the telescope subtends a larger angle at the eye than the object does
C) the intermediate image formed by the objective lens is greatly magnified
D) both the objective and eyepiece form real images

Question 45

An astronomical telescope has a barrel length of 33 cm and an angular magnification of 10.What are the focal lengths of the objective and the eyepiece in that order?

A) 0.3 m, 3 m
B) 30 cm, 3 cm
C) 20 cm,13 cm
D) 3 cm, 30 cm

Question 46

Reflecting telescopes may suffer with what kind of aberration(s)?

A) spherical
B) chromatic
C) spherical and chromatic
D) cinematic
E) Brewster and parabolic

Question 47

A TEM is a nonoptical microscope.What does TEM stand for?

A) transverse electron magnifier
B) telescopic emulation machine
C) triple emission magnifier
D) transmission electron microscope
E) none of these answers are correct

Question 48

An astronomical telescope has a magnifying power of 200 $\times$ when operated with a 3.50 cm eyepiece.What is the focal length of the objective of this telescope?

A) 204 cm
B) 196 cm
C) 700 cm
D) 57.0 cm
E) 30.0 cm

Question 49

Which of the following is not necessarily true about the image produced by a pinhole camera?

A) The image is inverted
B) The image is smaller than the object
C) The image is real
D) None of the above is absolutely required
E) All of the above are absolutely required

Question 50

An astronomical telescope is made with lenses of focal lengths 80.0 and 2.00 cm.What is the barrel length on this telescope?

A) 80.0 cm
B) 82.0 cm
C) 78.0 cm
D) 105 cm
E) 127 cm

Question 51

The objective of an astronomical telescope has a focal length of 900 mm.The telescope has eyepieces of focal lengths 20 mm,15 mm,and 10 mm.What is the highest magnification for this telescope?

A) 920 $\times$
B) 900 $\times$
C) 880 $\times$
D) 90 $\times$
E) 60 $\times$

Question 52

A compound microscope gives a magnification of 200 $\times$ with an eyepiece of focal length 2.00 cm.If the eyepiece is replaced with an eyepiece of focal length 1.50 cm,what magnification results?

A) 150 $\times$
B) 133 $\times$
C) 89 $\times$
D) 267 $\times$
E) 300 $\times$

Question 53

An astronomical telescope operates at 100 power using a 2.00 cm eyepiece.How long is the barrel of the telescope?

A) 52.0 cm
B) 100 cm
C) 102 cm
D) 200 cm
E) 202 cm

Question 54

An astronomical telescope is made with lenses of focal lengths 80.0 and 1.25 cm.What magnifying power does this telescope provide?

A) 10
B) 81
C) 79
D) 64
E) 41

Question 55

What causes chromatic aberration?

A) the index of refraction is a function of wavelength
B) the outer edges of the lens produce a focus at a different point from the central rays
C) the absorption of light in the glass is a function of wavelength
D) the coefficient of reflection is a function of wavelength

Question 56

An astronomical telescope is made with lenses of focal length 80.0 cm and 2.00 cm.Two stars in the sky are separated by 0.080 $^{\circ}$ .What angle of separation do they have when viewed in the telescope?

A) 40 $^{\circ}$
B) 6.4 $^{\circ}$
C) 3.2 $^{\circ}$
D) 1.6 $^{\circ}$
E) 0.080 $^{\circ}$

Question 57

There are two lenses in a microscope because

A) the objective is a converging lens and the eyepiece is a diverging lens.
B) the objective is a diverging lens and the eyepiece is a diverging lens.
C) the objective is a diverging lens and the eyepiece is a converging lens.
D) the objective is a converging lens and the eyepiece is a converging lens.

Question 58

A telescope is set up in introductory physics lab using a 10 cm lens and a 50 cm lens.Since both lenses are the same diameter it is not evident which one to use as the eyepiece and which one to use as the objective.If one uses the 50 cm lens as the eyepiece,what power results?

A) 500 $\times$
B) 5 $\times$
C) 0.2 $\times$
D) 0.002 $\times$
E) one cannot look through the system in this direction

Question 59

A fixed focus camera has a focal length of 35.0 mm.How far must the lens be moved in order to change focus from an object that is 20.0 m away to one that is 3.0 m away?

A) 0.34 mm
B) 0.41 mm
C) 0.35 mm
D) 0.47 mm

Question 60

What causes spherical aberration?

A) the lens surface is not perfectly smooth
B) the outer edges of the lens produce a focus at a different point than the central rays
C) light is an electromagnetic wave with intrinsic diffraction properties
D) the absorption of light in the glass is a function of wavelength

Question 61

The corrective lenses of a person suffering from which vision ailment could be used to start a fire?

A) Myopia
B) no eyeglass lenses can be used to make a fire.
C) astigmatism
D) hyperopia
E) cataracts

Question 62

You use a camera with a lens whose focal length is 50.00 mm,and are taking a picture of a 2.500 m tall statue that is located 7.200 m from the lens.If the image height on the film is 18.20 mm,what is the distance from the lens to the film?

A) 5.035 cm
B) need more information
C) 6.32 mm
D) 5.242 cm

Question 63

In a Galilean telescope,the eyepiece is a diverging lens,while the objective lens is a converging lens.This means that:

A) The image that the observer looks at is inverted
B) The image that the observer looks at subtends a larger angle than the object does
C) The image that the observer looks at is virtual
D) The image that the observer looks at is real

Question 64

A simple magnifier of refractive power 15.0 D is used to observe a beetle on a student's desk.If the image of the beetle is formed at her nearpoint of 25 cm,how large is the image compared to the beetle?

A) 4.0
B) 2.0
C) 5.9
D) 1.5
E) 0.50

Question 65

The pupil of the eye controls:

A) the focal length of the eye
B) the far point
C) the near point
D) the amount of light reaching the retina
E) none of these.

Question 66

A simple magnifier of refractive power 15.0 D is used to observe a beetle on a student's desk.If the image of the beetle is formed at her nearpoint of 25 cm,how far is the beetle from the magnifier?

A) 50 cm
B) 6.3 cm
C) 4.2 cm
D) 17 cm

Question 67

A simple magnifier of refractive power 15.0 D is used to observe a beetle on a student's desk.If the image of the beetle is twice as large as the beetle itself,where is the image formed relative to the lens?

A) 4.5 cm
B) 8.3 cm
C) 5.0 cm
D) 3.6 cm
E) 5.6 cm

Question 68

The image produced by the lens of the eye on the retina when properly focused is:

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