Question 1

A lens of focal length 45 mm is mounted on a 35 mm camera.The lens aperture is set at f/ 2 and the shutter speed set at 1/2000 s.The aperture diameter,in mm,is closest to:

Accepted Answer

A)  23
B)  16
C)  19
D)  26
E)  29 A

Question 2

The objective and the eyepiece of a refracting astronomical telescope have focal lengths of 320 cm and 4.0 cm,respectively.The telescope is used to view Neptune and the final image is set at infinity.The diameter of Neptune is 4.96 F1F1F1S1F1F1F10 107 m and the distance from Earth at the time of observation is 4.4 F1F1F1S1F1F1F10 1012 m.The angle subtended by the final telescopic image of Neptune,in m rad,is closest to:

Accepted Answer

A)  0.9
B)  1.1
C)  1.3
D)  1.5
E)  1.7 A

Question 3

A lens of focal length 45 mm is used as a magnifier.The object being viewed is 6.8 mm long,and is positioned at the focal point of the lens.The lens is moved closer to the object,so that the image is now 25 cm from the lens.The distance the lens has been moved,in cm,is closest to:

Accepted Answer

A)  0.69
B)  0.76
C)  0.62
D)  0.55
E)  0.48 A

Question 4

What optical element would you need and how would you use it to determine the focal length of a concave lens.

Accepted Answer

The answer of What optical element would you need and...

Question 5

A 35 mm camera equipped with a 45 mm focal length lens is used to photograph a tree 15 m tall.The aperture of the lens is set at f/ 2.The aperture diameter at f/ 2,in mm,is closest to:

Accepted Answer

A)  23
B)  14
C)  18
D)  27
E)  31

Question 6

A farsighted boy has a near point at 2.0 m and requires eyeglasses to correct his vision.Corrective lenses are available in increments in power of 0.25 diopters.The eyeglasses should have lenses of the lowest power for which the near point is no further than 25 cm.The boy borrows eyeglasses that have a power of + 2.75 diopters.With these eyeglasses,the near point of the boy,in cm,is closest to:

Accepted Answer

A)  31
B)  28
C)  33
D)  37
E)  40

Question 7

Situation 19.3
The angular magnification of a refracting telescope is 40.When the object and final image are both at infinity,the distance between the eyepiece and the objective is 143.5 cm.The telescope is used to view a distant radio tower.The real image of the tower,formed by the objective,is 6.0 mm in height.The focal point of the eyepiece is positioned at the real image.
-In Situation 19.3,the angle subtended by the final image of the tower is closest to:

Accepted Answer

A)  0.15 rad
B)  0.17 rad
C)  0.19 rad
D)  0.21 rad
E)  0.23 rad

Question 8

A blue filter absorbs the blue light as white light passes through it.

Accepted Answer

A) True 
 B)False

Question 9

Situation 19.1
The objective of a microscope has a focal length of 2.4 mm and the eyepiece has an angular magnification of 15.The object is positioned 0.06 mm beyond the focal point of the objective.The focal point of the eyepiece is positioned at the real image formed by the objective.
-In Situation 19.1,the separation between the objective and the eyepiece,in mm,is closest to:

Accepted Answer

A)  98
B)  102
C)  107
D)  111
E)  115

Question 10

A machinist with normal vision has a near point at 25 cm.The machinist wears eyeglasses in order to do close work.The power of the lenses is + 4.25 diopters.With these eyeglasses,the near point of the machinist,in cm,is closest to:

Accepted Answer

A)  12
B)  10
C)  7
D)  15
E)  17

Question 11

You use a $600 lens from a photocopy machine hoping to make a good telescope.Yet the image is disappointingly bad.Why?

Accepted Answer

The answer of You use a $600 lens from a...

Question 12

The intensity of light decreases as the f-number of a camera lens is increased.

Accepted Answer

A) True 
 B)False

Question 13

A farsighted boy has a near point at 2.3 m and requires eyeglasses to correct his vision.Corrective lenses are available in increments in power of 0.25 diopters.The eyeglasses should have lenses of the lowest power for which the near point is no further than 25 cm.The correct choice of lens power for eyeglasses,in diopters,is:

Accepted Answer

A)  + 3.75
B)  + 3.50
C)  + 3.25
D)  + 4.00
E)  + 4.25

Question 14

A magnifier consists of a converging lens with the object distance greater than the focal length of the lens.

Accepted Answer

A) True 
 B)False

Question 15

The objective lens of an astronomical telescope has a focal length of 60 cm and the eyepiece has a focal length of 2 cm.How far apart should the lenses be placed in order to form a final image at infinity?

Accepted Answer

A)  44 cm
B)  58 cm
C)  76 cm
D)  60 cm
E)  62 cm

Question 16

Situation 19.2
The objective and the eyepiece of a microscope have focal lengths of 4.0 mm and 25 mm,respectively.The objective produces a real image 30 times the size of the object.The final image is viewed at infinity.The near point of the microscope user is at 25 cm.
-In Situation 19.2,the distance between the object and the focal point of the objective,in mm,is closest to:

Accepted Answer

A)  0.13
B)  0.18
C)  0.23
D)  0.28
E)  0.33

Question 17

The image of a tree on a 35 mm color slide is 1.7 mm high.It is to be projected onto a screen 8.0 m from the slide,and is to appear 559 mm high.(a)What focal length lens (in meters)is needed? (b)What is the distance in meters between the lens and the slide? (c)What is the magnification of the system?

Accepted Answer

A)  (a) 0.02 m (b) 0.02 m(c) 329
B)  (a) 0.02 m (b) 7.98 m(c) 0.00
C)  (a) 0.02 m (b) -0.02 m(c) 0.00
D)  (a) 0.02 m (b) -8.02 m(c) 0.00

Question 18

Situation 19.1
The objective of a microscope has a focal length of 2.4 mm and the eyepiece has an angular magnification of 15.The object is positioned 0.06 mm beyond the focal point of the objective.The focal point of the eyepiece is positioned at the real image formed by the objective.
-In Situation 19.1,the overall magnification of the microscope is closest to:

Accepted Answer

A)  400
B)  450
C)  500
D)  550
E)  600

Question 19

A 35 mm camera equipped with a 40 mm focal length lens is used to photograph a tree 17 m tall.The aperture of the lens is set at f/8.A 32 mm high image of the tree on the film is required.The required distance,between the tree and the camera,to take the photograph is closest to:

Accepted Answer

A)  21 m
B)  22 m
C)  23 m
D)  24 m
E)  26 m

Question 20

To give large magnification,a telescope should have

Accepted Answer

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

Exam 19: Optical Instruments

A lens of focal length 45 mm is mounted on a 35 mm camera.The lens aperture is set at f/ 2 and the shutter speed set at 1/2000 s.The aperture diameter,in mm,is closest to:

A lens of focal length 45 mm is used as a magnifier.The object being viewed is 6.8 mm long,and is positioned at the focal point of the lens.The lens is moved closer to the object,so that the image is now 25 cm from the lens.The distance the lens has been moved,in cm,is closest to:

What optical element would you need and how would you use it to determine the focal length of a concave lens.

A 35 mm camera equipped with a 45 mm focal length lens is used to photograph a tree 15 m tall.The aperture of the lens is set at f/ 2.The aperture diameter at f/ 2,in mm,is closest to:

A blue filter absorbs the blue light as white light passes through it.

A machinist with normal vision has a near point at 25 cm.The machinist wears eyeglasses in order to do close work.The power of the lenses is + 4.25 diopters.With these eyeglasses,the near point of the machinist,in cm,is closest to:

You use a $600 lens from a photocopy machine hoping to make a good telescope.Yet the image is disappointingly bad.Why?

The intensity of light decreases as the f-number of a camera lens is increased.

A magnifier consists of a converging lens with the object distance greater than the focal length of the lens.

The objective lens of an astronomical telescope has a focal length of 60 cm and the eyepiece has a focal length of 2 cm.How far apart should the lenses be placed in order to form a final image at infinity?

A 35 mm camera equipped with a 40 mm focal length lens is used to photograph a tree 17 m tall.The aperture of the lens is set at f/8.A 32 mm high image of the tree on the film is required.The required distance,between the tree and the camera,to take the photograph is closest to:

To give large magnification,a telescope should have