Question 1

The length of a telescope is 2.20 m and the focal length of the eyepiece is 1.9 cm. What is the focal length of the objective lens?

Accepted Answer

A)  45 cm 
B)  111 cm 
C)  41 cm 
D)  16 cm 
E)  218 cm 
A)  45 cm 
B)  111 cm 
C)  41 cm 
D)  16 cm 
E)  218 cm

Question 2

A magnifying glass uses a converging lens with a refractive power of 20 diopters. What is the angular magnification if the image is to be viewed by a relaxed eye with a near point of 25 cm?

Accepted Answer

A)  5.0 
B)  3.0 
C)  4.0 
D)  2.0 
E)  1.0 
A)  5.0 
B)  3.0 
C)  4.0 
D)  2.0 
E)  1.0

Question 3

As a treatment for cataracts (a cloudiness of the lens of the eye), the natural lens is removed and a plastic lens is implanted. After this is done a person can see distant objects clearly, but he cannot
Accommodate to focus on nearby objects. If such a person wanted to read a book at a distance of 25
Cm, he would have to wear contact lenses having a diopter power of

Accepted Answer

A)  -1.78 diopters 
B)  +3.33 diopters 
C)  -4.00 diopters 
D)  +4.00 diopters 
E)  +2.78 diopters 
A)  -1.78 diopters 
B)  +3.33 diopters 
C)  -4.00 diopters 
D)  +4.00 diopters 
E)  +2.78 diopters

Question 4

A $35 - \mathrm { mm }$ single lens reflex (SLR) digital camera is using a lens of focal length $35.0 \mathrm {~mm}$ to photograph a person who is $1.80 \mathrm {~m}$ tall and located $3.60 \mathrm {~m}$ from the lens.
(a) How far is the CCD sensor from the lens when the person is in focus?
(b) How tall is the person's image on the CCD sensor?

Accepted Answer

(a) 3.53 c

Question 5

The focal lengths of the objective lens and the eyepiece in a microscope are 2.90 mm and 2.50 cm, respectively. An object is placed 3.00 mm from the objective. The image of this object is viewed
With the eyepiece adjusted for minimum eyestrain for persons with a near point of 25 cm. What is
The distance between the objective and the eyepiece?

Accepted Answer

A)  9.0 cm 
B)  15 cm 
C)  11 cm 
D)  13 cm 
E)  9.9 cm 
A)  9.0 cm 
B)  15 cm 
C)  11 cm 
D)  13 cm 
E)  9.9 cm

Question 6

A microscope has an objective lens of focal length 1.40 mm and an eyepiece of focal length 20.00 mm. It is adjusted for minimum eyestrain for persons with a near point of 25.0 cm. A blood
Sample is placed 1.50 mm from the objective. The magnitude of the overall magnification is closest
To

Accepted Answer

A)  180. 
B)  18. 
C)  37. 
D)  370. 
A)  180. 
B)  18. 
C)  37. 
D)  370.

Question 7

A nearsighted man wears contact lenses of -3.00 diopters. With these lenses, his corrected
near point is 25.0 cm. What is his uncorrected near point?

Accepted Answer

The answer of A nearsighted man wears contact lenses of...

Question 8

A person with normal eyesight uses a converging lens of focal length $10 \mathrm {~cm}$ as a magnifying glass to finish an engraving job. To see detail, he holds the lens very close to his eyes. What is the maximum angular magnification of the lens under these circumstances?

Accepted Answer

A)  $8.5$ 
B)  $6.5$ 
C)  $3.5$ 
D)  $4.5$
Е) $7.5$ 
A)  $8.5$ 
B)  $6.5$ 
C)  $3.5$ 
D)  $4.5$
Е) $7.5$

Question 9

The focal length of a magnifying glass is 15 cm. If the near point of a person is 25 cm, what is the angular magnification of the glass for this person when his eyes are focused at infinity?

Accepted Answer

A)  $1.7$ 
B)  $2.7$ 
C)  $3.7$ 
D)  $5.7$ 
E)  $4.7$ 
A)  $1.7$ 
B)  $2.7$ 
C)  $3.7$ 
D)  $5.7$ 
E)  $4.7$

Question 10

A compound microscope consists of an objective lens of focal length f0 and an eyepiece
that by itself produces an angular magnification 25.0. The microscope is designed so that
the object to be viewed is on the left side of the objective lens and is focused in a plane that
is 28.00 cm away from the right-hand (or inside) focal point of the objective lens. When
properly adjusted, the eyepiece and the objective lens are 29.90 cm apart. The eyepiece
magnification is based on an image at infinity and a near point at 25.0 cm. What is f0?

Accepted Answer

The answer of A compound microscope consists of an objective...

Question 11

The eyepiece of a compound microscope has a focal length of 2.50 cm, and the objective has a focal length of 1.60 cm. The two lenses are separated by 14.0 cm. The microscope is used by a person
With normal eyes, having a near point at 25 cm. What is the magnitude of the magnification of the
Microscope?

Accepted Answer

A)  219 
B)  72 
C)  88 
D)  115 
E)  180 
A)  219 
B)  72 
C)  88 
D)  115 
E)  180

Question 12

A crystal is irradiated with x-rays with a wavelength of $0.120 \mathrm {~nm}$. The atomic planes in the crystal are separated by $0.21 \mathrm {~nm}$. At what angles of incidence with respect to the normal will the $x$-rays reflect from the crystal?

Accepted Answer

A)  only $73 ^ { \circ }$ 
B)  only $55 ^ { \circ }$ 
C)  $73 ^ { \circ } , 55 ^ { \circ } , 31 ^ { \circ }$ 
D)  only $73 ^ { \circ }$ and $31 ^ { \circ }$ 
A)  only $73 ^ { \circ }$ 
B)  only $55 ^ { \circ }$ 
C)  $73 ^ { \circ } , 55 ^ { \circ } , 31 ^ { \circ }$ 
D)  only $73 ^ { \circ }$ and $31 ^ { \circ }$

Question 13

A slide projector needs to focus the image of a 24.0-mm × 36.0-mm slide onto a square
screen 1.50 m on each side. You want to fill the screen as completely as possible without
any of the image falling beyond the screen. Due to space constraints in the projector, the
slide must be placed 10.5 cm from the lens.
(a) What magnification does the projector produce?
(b) How far from the lens should the screen be placed?
(c) What focal length projector lens is needed?

Accepted Answer

(a) 41.7,

Question 14

The objective lens of a microscope has a focal length of 2.4 mm and the eyepiece has an angular magnification of 15. The object is positioned 0.060 mm beyond the focal point of the objective. The
Focal point of the eyepiece is positioned at the real image formed by the objective. The near point
Of the microscope user is at 25 cm. What is the distance between the objective lens and the
Eyepiece?

Accepted Answer

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

Question 15

Light of wavelength 500 nm illuminates a round 0.50-mm-diameter hole. A screen is placed 6.0 m past the slit. What is the width of the central bright circle on the screen?

Accepted Answer

A)  $3700 \mu \mathrm { m }$ 
B)  $7.3 \mathrm {~mm}$ 
C)  $260 \mu \mathrm { m }$ 
D)  $15 \mathrm {~mm}$ 
A)  $3700 \mu \mathrm { m }$ 
B)  $7.3 \mathrm {~mm}$ 
C)  $260 \mu \mathrm { m }$ 
D)  $15 \mathrm {~mm}$

Question 16

A nearsighted person has a near point of 12 cm and a far point of 17 cm. If the corrective
lens is 2.0 cm from his eye, (a) what lens power will enable this person to see distant
objects clearly, and (b) what then will be the new near point of his eye?

Accepted Answer

(a) -6.7 d

Question 17

What is the power of the lens that has a focal length of 40 cm and a diameter if 5.0 cm?

Accepted Answer

A)  +2.7 diopters 
B)  -2.5 diopters 
C)  +0.20 diopters 
D)  +2.5 diopters 
E)  +20 diopters 
A)  +2.7 diopters 
B)  -2.5 diopters 
C)  +0.20 diopters 
D)  +2.5 diopters 
E)  +20 diopters

Question 18

A lens of focal length 90 mm is used as a magnifier by a person with a near point of 25 cm. The object being viewed is 9.9 mm long, and is positioned at the focal point of the lens. What is the
Angle subtended by the image at infinity, in milliradians?

Accepted Answer

A)  73 mrad 
B)  110 mrad 
C)  147 mrad 
D)  37 mrad 
E)  183 mrad 
A)  73 mrad 
B)  110 mrad 
C)  147 mrad 
D)  37 mrad 
E)  183 mrad

Question 19

The objective lens of a telescope has a focal length of 2.0 m and its eyepiece has a focal length of 1.0 cm. What is the magnification of this telescope when viewing Jupiter?

Accepted Answer

A)  0.50 
B)  0.0050 
C)  20 
D)  200 
E)  2.0 
A)  0.50 
B)  0.0050 
C)  20 
D)  200 
E)  2.0

Question 20

For an eye that is 2.4 cm in diameter, what must be the range of focal lengths of the lens to
focus objects from the near point (25 cm) to infinity on the retina?

Accepted Answer

The answer of For an eye that is 2.4 cm...

Exam 25: Optical Instruments

The length of a telescope is 2.20 m and the focal length of the eyepiece is 1.9 cm. What is the focal length of the objective lens?

A magnifying glass uses a converging lens with a refractive power of 20 diopters. What is the angular magnification if the image is to be viewed by a relaxed eye with a near point of 25 cm?

A microscope has an objective lens of focal length 1.40 mm and an eyepiece of focal length 20.00 mm. It is adjusted for minimum eyestrain for persons with a near point of 25.0 cm. A blood Sample is placed 1.50 mm from the objective. The magnitude of the overall magnification is closest To

A nearsighted man wears contact lenses of -3.00 diopters. With these lenses, his corrected near point is 25.0 cm. What is his uncorrected near point?

A person with normal eyesight uses a converging lens of focal length 10 cm10 \mathrm {~cm}10 cm as a magnifying glass to finish an engraving job. To see detail, he holds the lens very close to his eyes. What is the maximum angular magnification of the lens under these circumstances?

The focal length of a magnifying glass is 15 cm. If the near point of a person is 25 cm, what is the angular magnification of the glass for this person when his eyes are focused at infinity?

A crystal is irradiated with x-rays with a wavelength of 0.120 nm0.120 \mathrm {~nm}0.120 nm . The atomic planes in the crystal are separated by 0.21 nm0.21 \mathrm {~nm}0.21 nm . At what angles of incidence with respect to the normal will the xxx -rays reflect from the crystal?

Light of wavelength 500 nm illuminates a round 0.50-mm-diameter hole. A screen is placed 6.0 m past the slit. What is the width of the central bright circle on the screen?

A nearsighted person has a near point of 12 cm and a far point of 17 cm. If the corrective lens is 2.0 cm from his eye, (a) what lens power will enable this person to see distant objects clearly, and (b) what then will be the new near point of his eye?

What is the power of the lens that has a focal length of 40 cm and a diameter if 5.0 cm?

A lens of focal length 90 mm is used as a magnifier by a person with a near point of 25 cm. The object being viewed is 9.9 mm long, and is positioned at the focal point of the lens. What is the Angle subtended by the image at infinity, in milliradians?

The objective lens of a telescope has a focal length of 2.0 m and its eyepiece has a focal length of 1.0 cm. What is the magnification of this telescope when viewing Jupiter?

For an eye that is 2.4 cm in diameter, what must be the range of focal lengths of the lens to focus objects from the near point (25 cm) to infinity on the retina?

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A person with normal eyesight uses a converging lens of focal length $10 \mathrm {~cm}$ as a magnifying glass to finish an engraving job. To see detail, he holds the lens very close to his eyes. What is the maximum angular magnification of the lens under these circumstances?

A crystal is irradiated with x-rays with a wavelength of $0.120 \mathrm {~nm}$ . The atomic planes in the crystal are separated by $0.21 \mathrm {~nm}$ . At what angles of incidence with respect to the normal will the $x$ -rays reflect from the crystal?