Deck 25: Optical Instruments

Question 1

A camera has a lens of focal length 50 mm and a speed of f/2.0.What is the diameter of the lens?

A) 12.5 mm
B) 25.0 mm
C) 50 mm
D) 100 mm
E) ​2.0 mm

Answer 1

25.0 mm

Question 2

A 1.7-m tall woman stands 8.0-m in front of a camera with a 5.0-cm focal length lens.What is the size of the image formed on film?

A) 23.5 cm
B) 2.7 cm
C) 1.1 cm
D) 68.0 cm
E) ​0.37 cm

Answer 2

1.1 cm

Question 3

A camera uses a:

A) converging lens to form a real image.
B) converging lens to form an imaginary image.
C) diverging lens to form a real image.
D) diverging lens to form an imaginary image.

Answer 3

converging lens to form a real image.

Question 4

Which term below identifies the eye defect characterized by an inability to see distant objects clearly?

A) myopia
B) presbyopia
C) hyperopia
D) astigmatism

Question 5

The pupil of the eye increases in size under which condition?

A) eye is focused on a distant object
B) eye is focused on a nearby object
C) object viewed is dimly illuminated
D) object viewed is well illuminated

Question 6

Tripling the aperture diameter of a camera lens will change the light intensity admitted to the film by what factor?

A) 0.11
B) 0.33
C) 3.0
D) 9.0
E) ​12.0

Question 7

A camera lens is initially set at f/8 for a shutter speed of 1/250 s.If the amount of lighting on the subject is unchanged,and the lens is set at f/4,what is the proper shutter speed at this setting?

A) 1/1000 s
B) 1/500 s
C) 1/250 s
D) 1/2 s
E) 1/8​ s

Question 8

A low f-number:

A) allows a smaller depth of field.
B) allows using a faster shutter speed.
C) causes less spherical aberration.
D) is not related to any of the above options.

Question 9

A camera is used to photograph the full moon,which has an angular diameter of 0.53°.The image on the film is 2.3 mm in diameter.What is the focal length of the lens?

A) 2.3 mm
B) 500 mm
C) 250 mm
D) 790 mm
E) ​25.5 mm

Question 10

Tripling the focal length in a telephoto lens,while keeping the aperture size constant,will change the f-number by what factor?

A) 1/9
B) 1/3
C) 3
D) 9
E) ​1/6

Question 11

I take two pictures of my dog Kaycee.I use the same film and level of illumination for both pictures,but I quadruple the f-number for the second picture.By what factor will the required time of exposure change if the film is to receive the same total light energy?

A) 0.06
B) 0.25
C) 4.0
D) 16.0
E) ​3.0

Question 12

Tripling the focal length of a telephoto lens,while holding aperture size constant,will change the light intensity admitted to the film by what factor?

A) 0.11
B) 0.33
C) 3.0
D) 9.0
E) ​0.50

Question 13

A converging lens will be prescribed by the eye doctor to correct which of the following?

A) farsightedness
B) glaucoma
C) nearsightedness
D) astigmatism

Question 14

Doubling the aperture diameter of a camera lens will change the f-number by what factor?

A) 1/4
B) 1/2
C) 2
D) 4
E) 1/​3

Question 15

What is the f-number of a camera lens that has an aperture-opening diameter of 0.30 cm and a focal length of 6.0 cm?

A) 0.30
B) 1.8
C) 20
D) 6.0
E) ​0.05

Question 16

A diverging lens will be prescribed by the eye doctor to correct which of the following?

A) myopia
B) presbyopia
C) hyperopia
D) astigmatism

Question 17

The ciliary muscle is instrumental in changing the shape of which eye part?

A) iris
B) lens
C) pupil
D) retina

Question 18

The ciliary muscle of the eye is relaxed under which condition?

A) eye is focused on a distant object
B) eye is focused on a nearby object
C) subject being viewed is well illuminated
D) subject being viewed is dimly illuminated

Question 19

Changing the f-number of a camera by three stops by going from f/11 to f/32 will change the intensity of the light hitting the film by a factor of:

A) 8.
B) 4.
C) 1/4.
D) 1/8.
E) ​32.

Question 20

Quadrupling the f-number of a camera lens will change the light intensity admitted to the film by what factor?

A) 1/16
B) 1/4
C) 4
D) 16
E) ​3

Question 21

A thin lens of focal length 20 cm is placed in contact with a 40-diopter thin lens.What is the power of the combined lenses?

A) 1/4 diopter
B) 35.0 diopters
C) 45.0 diopters
D) 80 diopters
E) ​4 diopters

Question 22

While a camera has film where the image is formed,the eye forms the image on the:

A) pupil.
B) cornea.
C) retina.
D) optic nerve.

Question 23

A nearsighted person cannot see objects clearly beyond 70 cm (the far point).If the patient has no astigmatism and contact lenses are prescribed,what is the power of the lens required to correct the patient's vision?

A) −0.7 diopters
B) −1.4 diopters
C) −2.9 diopters
D) −7.0 diopters
E) ​-700 diopters

Question 24

Two thin lenses in combination are placed in contact with each other along a common axis.They have powers of 70 and -20 diopters,respectively.What is their combined power?

A) 25 diopters
B) 50 diopters
C) 90 diopters
D) -25 diopters
E) ​70 diopters

Question 25

A person with limited accommodation is prescribed lenses of power -3.0 diopters for distant vision.Bifocal inserts are added to these lenses to allow vision at 50 cm.What is the power of the inserts?

A) -1.0 diopters
B) 2.0 diopters
C) 5.0 diopters
D) 50​ diopters
E) ​This does not work with negative diopter distance lenses.

Question 26

A person has a near point of 40 cm and a far point of 1.0 m.When looking through lenses of focal length -1.0 m,what is the nearest an object can be to be seen clearly?

A) 29 cm
B) 67 cm
C) 134 cm
D) 140 cm
E) ​68 cm

Question 27

Young children that need glasses are rarely prescribed bifocals.Why?

A) They are almost always nearsighted.
B) They are almost always farsighted.
C) They have considerable accommodation power.
D) Parents don't go for the additional expense.

Question 28

Which term identifies the defect where the lens produces a line image of a point source?

A) myopia
B) presbyopia
C) hyperopia
D) astigmatism

Question 29

You are designing eyeglasses for someone whose near point is 60 cm.What focal length lens should you prescribe so that an object can be clearly seen when placed at 25 cm in front of the eye?

A) −18 cm
B) 18 cm
C) 43 cm
D) 60 cm
E) ​-43 cm

Question 30

If a person has hyperopia that person:

A) may have an unusually long eyeball.
B) cannot see near objects clearly.
C) cannot relax the ciliary muscle adequately.
D) cannot form images behind the retina.

Question 31

Which eye defect is corrected by a lens having different curvatures in two perpendicular directions?

A) myopia
B) presbyopia
C) hyperopia
D) astigmatism

Question 32

The eye changes its f-number by:

A) using the iris to change the size of the pupil.
B) using the ciliary muscle to change the focal length of the lens.
C) Both a & b are correct.
D) The eye does not change its f-number.

Question 33

A given individual is unable to see objects clearly when they are beyond 100 cm.What focal length lens should be used to correct this problem?

A) −100 cm
B) −33.3 cm
C) −20 cm
D) 75 cm
E) ​100 cm

Question 34

A lens with a focal length of 20 cm has what power?

A) 5.0 diopters
B) 0.2 diopters
C) 2 diopters
D) -5.0 diopters
E) 0.02​ diopters

Question 35

Glaucoma occurs because:

A) the eye cannot accommodate properly.
B) the shape or size of the eye is not normal.
C) there is too much pressure in the fluid in the eyeball.
D) the lens is partially or totally opaque.

Question 36

If a person is farsighted the corrective lens will:

A) take an object at the near point and form an image at 25 cm.
B) take an object at 25 cm and form an image at the near point.
C) take an object at infinity and form an image at 25 cm.
D) take an object at infinity and form an image at the near point.

Question 37

Two thin lenses have powers P₁ and P₂,measured in diopters.If these lenses are placed in contact with one another,the resulting power is:

A) more than both P₁ and P₂.
B) less than both P₁ and P₂.
C) half-way between P₁ and P₂.
D) P₁ + P₂.

Question 38

A farsighted person with astigmatism would be prescribed a lens that is:

A) diverging only.
B) both converging and cylindrical..
C) diverging only..
D) both converging and cylindrical.

Question 39

In the normal eye the ciliary muscles that control the lens will relax:

A) when viewing objects at the near point.
B) when viewing objects at infinity.
C) when viewing objects at a distance of 20 ft.
D) only when a person has his/her eyes closed.

Question 40

The "normal" eye has a near point of 25 cm.If a given individual's near point is 73 cm,for what problem will the eye doctor prescribe correction?

A) myopia
B) presbyopia
C) hyperopia
D) astigmatism
E) ​color blindness

Question 41

A simple magnifier makes an image appear at the near point distance from the eye of the viewer (25 cm).What is the magnifying power of the magnifier if it is constructed of a lens of focal length of 5.0 cm?

A) 1.2
B) 5.11
C) 7
D) 62
E) ​5.62

Question 42

What is the resolving power of a diffraction grating that is capable of just distinguishing between two wavelengths of 568.20 nm and 569.60 nm? (1 nm = 10−⁹ m)

A) 1.10
B) 406
C) 487
D) 812
E) ​568.9

Question 43

A lens is used as a magnifier.Which of the following statements is incorrect?

A) The lens is convex.
B) The dioptric power of the lens is positive.
C) The magnification is greatest when the eye focuses at the near point.
D) The focal length of the lens must be negative.

Question 44

A person's prescription for bifocals is -0.35 diopter for distant vision and +3.10 diopters for near vision,the near vision being accomplished by inserts into the distant vision lens.What is the net power of the near vision correction?

A) 2.75 diopters
B) 3.10 diopters
C) 3.45 diopters
D) 1.085 diopters
E) ​More information is needed.

Question 45

Light with a wavelength of 410 nm shines through a lens with an aperture diameter of 0.60 cm.Use Rayleigh's criterion to determine the limiting angle of resolution.(1 nm = 10−⁹ m)

A) 8.3 × 10−⁵ rad
B) 2.8 × 10−⁹ rad
C) 1.8 × 10−⁴ rad
D) 7.9 × 10−⁷ rad
E) ​0.6 × 10−⁷ rad

Question 46

An astronomical telescope has an objective lens with focal length f_o and has an eyepiece with focal length f_e.A second telescope has objective and eyepiece lenses with quadruple the focal length of the first telescope.Which telescope gives the greater magnification and by what factor?

A) The first telescope gives 16 times the magnification of the second.
B) The second telescope gives 16 times the magnification of the first.
C) Both telescopes give the same magnification.
D) The actual focal lengths must be known to answer this question.
E) ​The second telescope gives 4 times the magnification of the first.

Question 47

A microscope has an objective lens with an aperture of diameter 0.50 cm where a monochromatic light source of wavelength 580 nm is used to illuminate the object.It is determined that the minimum angle of resolution is 1.13 × 10−⁴ rad.If the illuminating source were replaced by an violet source of wavelength 420 nm,what would the minimum angle of resolution now become? (1 nm = 10−⁹ m)

A) 1.6 × 10−⁴ rad
B) 0.98 × 10−⁴ rad
C) 0.81 × 10−⁴ rad
D) 0.49 × 10−⁴ rad
E) ​1.13 × 10−⁴ rad

Question 48

What is the approximate magnification of a compound microscope with objective and eyepiece focal lengths of 0.30 cm and 4.1 cm,respectively,and a separation between lenses of 40 cm?

A) 320
B) 33
C) 32
D) 810
E) ​7.1

Question 49

A magnifier uses a:

A) converging lens to form a real image.
B) converging lens to form a virtual image.
C) diverging lens to form a virtual image.
D) diverging lens to form a real image.

Question 50

A refracting astronomical telescope has objective and eyepiece lenses of focal lengths 30.0 cm and 0.40 cm,respectively.What is the angular magnification of this instrument?

A) 25
B) 49
C) 75
D) 143
E) ​30.4

Question 51

The Palomar reflecting telescope has a parabolic mirror with an 80 m focal length.What is the magnification achieved when an eyepiece of focal length 2.5 cm is used?

A) 800
B) 1,100
C) 1,600
D) 3,200
E) ​2,000

Question 52

You are building a compound microscope with an objective lens of focal length 0.60 cm and an eyepiece lens of focal length 5.0 cm.You mount the lenses 18 cm apart.What is the maximum magnification of your microscope?

A) 5
B) 10
C) 75
D) 150
E) ​18

Question 53

A telescope has an objective lens with a focal length of 100 cm and an eyepiece of focal length 3.0 cm.What is the angular magnification of the telescope?

A) 30
B) 33
C) 75
D) 140
E) ​103

Question 54

Even relatively small astronomical telescopes are ordinarily not used for terrestrial observation because:

A) their images are too bright.
B) their images are too dim.
C) their images are inverted.
D) their images are not in color.

Question 55

A magnifying lens with a focal length of 10 cm has what maximum magnification? (Assume the near point is 25 cm).

A) 1.4
B) 3
C) 11
D) 4
E) ​10

Question 56

A compound microscope has an eyepiece that:

A) uses a real image from the objective as the object and forms its own real image.
B) uses a real image from the objective as the object and forms a virtual image.
C) uses a virtual image from the objective as the object and forms its own real image.
D) uses a virtual image from the objective as the object and forms its own virtual image.

Question 57

If the objective lens of a compound microscope is replaced with a lens of double the focal length while the eyepiece also has its focal length doubled,what will happen to the overall magnification of the microscope?

A) This will result in no change in the magnification.
B) The magnification doubles.
C) The magnification quadruples.
D) The magnification decreases.

Question 58

Doubling the focal length of the objective lens of a compound microscope will change the magnification by what factor?

A) 1/4
B) 1/2
C) 2
D) 4
E) ​

Question 59

The Yerkes refracting telescope has a 1-m diameter objective lens of focal length 20 m and an eyepiece of focal length 3.5 cm.What is the magnification of the planet Mars as seen through this telescope?

A) 140
B) 280
C) 570
D) 1,000
E) ​35

Question 60

A magnifying lens with a focal length of 30 cm has what magnification when the viewing eye is relaxed?

A) 7.14
B) 0.8
C) 1.3
D) 1.8
E) ​-0.2

Question 61

The pupil of a cat's eye narrows to a slit of width 0.5 mm in daylight.Assuming a wavelength of 500 nm,what is the angular resolution? (1 nm = 10−⁹ m)

A) 1 × 10−³ rad
B) 5 × 10−³ rad
C) 1 × 10−⁴ rad
D) 5 × 10−⁴ rad
E) ​2.5 × 10−⁴ rad

Question 62

A person can see well in the distance,but cannot do so at an arm's-length distance.To correct this,lenses that are ________ having a ________ power could be used.

A) thicker at their center than at the edges,positive
B) thicker at their center than at the edges,negative
C) thinner at their center than at the edges,positive
D) thinner at their center than at the edges,negative

Question 63

The 2.4-m diameter Hubble space telescope has been placed into Earth orbit by the space shuttle.Assuming a wavelength of 684 nm,what angular resolution could this telescope achieve by Rayleigh's criterion? (1 nm = 10−⁹ m)

A) 3.5 × 10−⁶ rad
B) 4.3 × 10−⁶ rad
C) 2.8 × 10−⁶ rad
D) 3.4 × 10−⁷ rad
E) ​2.4 × 10−⁶ rad

Question 64

A binary star system in the constellation Orion has an angular separation between the stars of 4*10−⁵ radians.Assuming a wavelength of 500 nm,what is the smallest aperture (diameter)telescope that will just resolve the two stars? (1 nm = 10−⁹ m)

A) 1.2 cm
B) 1.5 mm
C) 1.5 cm
D) 4.8 cm
E) ​20 mm

Question 65

Using a camera with a fixed focal length lens,how will decreasing the f-number affect the depth of field and the intensity of the light reaching the ccd (or film)?

A) The depth of field will increase as will the intensity of light reaching the ccd.
B) The depth of field will increase but the intensity of light reaching the ccd will decrease.
C) The depth of field will decrease as will the intensity of light reaching the ccd.
D) The depth of field will decrease but the intensity of light reaching the ccd will increase.

Question 66

Which of the following primarily determines the resolution of a telescope?

A) the barrel length
B) the focal length of the objective
C) the diameter of the objective
D) the diameter of the eyepiece

Question 67

The Michelson interferometer can make precise length measurements using which of the following phenomena?

A) force
B) interference
C) magnification
D) resolving power

Question 68

How many lines in a grating must be illuminated to obtain a resolving power of 400 in a fourth-order spectrum?

A) 1,600
B) 100
C) 400
D) 10
E) ​40

Question 69

If different filters are used with an astronomical telescope,which of the following would give the best resolution?

A) red
B) yellow
C) green
D) ​purple
E) ​All yield the same resolution.

Question 70

When using 545-nm light,how far is the adjustable mirror of a Michelson interferometer moved when 200 fringe shifts are counted?

A) 1.36 × 10^-6 m
B) 2.73 × 10^-5 m
C) 5.45 × 10^-5 m
D) 1.36 × 10^-4 m
E) ​2.7 × 10^-4 m

Question 71

Find the radius of a star image formed on the retina of the eye if the aperture diameter (the pupil)at night is 0.70 cm and the length of the eye is 3.2 cm.Assume the wavelength of starlight in the eye is 500 nm.(1 nm = 10−⁹ m)

A) 2.8 × 10−⁴ m
B) 5.6 × 10−⁴ m
C) 3.1 × 10−⁵ m
D) 2.8 × 10−⁶ m
E) ​3.2 × 10−⁴ m

Question 72

What must be the resolving power of a grating allowing a spectral line at 683.80 nm to be distinguished from another line differing by 0.33 nm? (1 nm = 10−⁹ m)

A) 2,100
B) 46
C) 4,300,000
D) 230
E) ​684

Question 73

An individual's eye pupil changes from a diameter of 3.5 mm to 1.4 mm as the illumination is increased.By what factor does the minimum angle of resolution change?

A) 0.5
B) 0.71
C) 2.2
D) 2.5
E) ​4.9

Question 74

The Michelson interferometer is a device that may be used to measure:

A) magnifying power of lenses.
B) light wavelength.
C) atomic masses.
D) electron charge.

Question 75

The eye parts iris,retina,cornea,and ciliary muscle,play roles related to ________,________,________,and ________ in a camera.

A) the aperture,the lens,the ccd,focusing
B) the aperture,the ccd,the lens,focusing
C) the lens,the aperture,focusing,the ccd
D) the lens,focusing,the ccd,the aperture

Question 76

What resolving power must a diffraction grating have in order to distinguish wavelengths of 686.30 nm and 687.50 nm? (1 nm = 10−⁹ m)

A) 343
B) 572
C) 686.9
D) 915
E) ​687.5

Question 77

A fringe shift occurs for every ________ wavelength movement of the adjustable mirror in a Michelson interferometer.

A) whole
B) half
C) quarter
D) eighth

Question 78

Why is it easier to see fine print in brighter light than in dimmer light?

A) This is not so,it is easier to see fine print in dimmer light than in brighter light.
B) Because the power (in diopters)of the eye increases as the light intensity increases.
C) In brighter light,the longer wavelengths dominate.
D) In brighter light,the f-number of the eye increases.

Question 79

A magnifying lens of power d (in diopters)gives what magnification when the viewing eye is relaxed assuming a near point of 25 cm?

A) 25d
B) 0.25/d
C) d/4
D) The correct answer is not given.