Essential University Physics, 3e (Wolfson) Chapter 31 Images and Optical Instruments
3 1. 1 Co nc e pt ua lQue s t i o ns 1) As you you walk away from a vertical plane mirror, your image in the mirror A) is always the same height. B) may or may not decrease in height, 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 v irtual image to a real image as you pass the focal point. ) decreases in height. Answer! A "ar! 1
#) $uppose you place your face in front of a concave con cave mirror. %hich %hich one of the following statements is correct& A) 'f you position yourself between the center of curvature and the focal point of the mirror, you will not be able to see a sharp image of your face. B) (o matter where you place yourself, a real image will be formed. C) our our image will always be inverted. D) our our image will be diminished in si*e. ) (one of these statements are true. Answer! A "ar! 1
+) %hich statements are true about a "'-A/ image& 0-here may be more than one correct choice.) A) 'ts location can be calculated, but bu t it cannot be viewed d directly irectly by your eye without using auiliary lenses. B) 't cannot be photographed. C) 't cannot be viewed on a screen. D) A plane mirror always forms a virtual image. ) A concave lens always forms a virtual image. Answer! C, D, "ar! 1
2) A conve lens has focal length f length f . 'f an ob3ect is located etremely e tremely far from the lens 0at infinity), the image formed is located what distance from the lens& A) infinity B) # f C) between f between f and and # f D) f ) between the lens and f and f Answer! D "ar! 1
1 Copyright 4 #516 7earson ducation, 'nc.
8) A conve lens has a focal length f length f . An ob3ect is placed at a distance between f between f and and # f on on a line perpendicular to the center of the lens. -he image formed is located at what distance from the lens& A) # f B) between f between f and and # f C) f D) between the lens and f and f ) farther than # f Answer! "ar! 1
6) A conve lens has a focal length f length f . An ob3ect is placed between infinity and # f from from the lens along a line perpendicular to the center of the lens. -he image is located at what distance from the lens& A) farther than # f B) # f C) between f between f and and # f D) f ) between the lens and f and f Answer! C "ar! 1
9) An ob3ect is placed in front of a lens which forms an image of the ob3ect. A) 'f the lens is conve, the image cannot be virtual. B) 'f the image is real, then it is also inverted. C) 'f the image is real, then it is also upright. D) 'f the image is virtual, then it is also inverted. ) 'f the image is virtual, the lens must be a diverging lens. Answer! B "ar! 1
:) %hich one of the following is a characteristic of a compound microscope& A) -he ob3ective is a diverging lens. B) -he eyepiece is a diverging lens. C) -he final image is real. D) -he image formed by the ob3ective is virtual. ) -he image formed by the ob3ective is real. Answer! "ar! 1
;) A simple refracting telescope provides large magnification by employing A) a short focal length ob3ective and a short focal length eyepiece. B) a short focal length ob3ective and a long focal length eyepiece. C) a long focal length ob3ective and a short focal length eyepiece. D) a long focal length ob3ective and a long focal length eyepiece. Answer! C "ar! 1
# Copyright 4 #516 7earson ducation, 'nc.
3 1 . 2 Pr o bl e ms 1)
#) A ob3ect is 1# cm in front of a concave spherical mirror, and the image is +.5 cm in front of the mirror. %hat is the focal length of the mirror& A) 5.#8 cm B) 18 cm C) 2.5 cm D) #.2 cm ) 1.+ cm Answer! D "ar! +
+) A concave spherical mirror with a radius of #5 cm creates a real image +5 cm from the mirror.
2) -he spherical side mirror on a car is conve and has a radius of curvature of #8 cm. Another car is following, #5 m behind the mirror. 'f the height of the car is 1.6 m, how tall is its image& A) 8.5 cm B) #.5 cm C) 2.5 cm D) +.5 cm ) 5.;; cm Answer! "ar! 1
+ Copyright 4 #516 7earson ducation, 'nc.
8) A man=s face is +5 cm in front of a concave spherical shaving mirror. 'f the image is erect and 1.8 times as large as his face, what is the radius of curvature of the mirror& A) 25 cm B) 65 cm C) 155 cm D) 125 cm ) 1:5 cm Answer! "ar! 1
6) A conve spherical mirror with a focal length of magnitude #8 cm has a 2.5>cm tall flower placed 155 cm in front of it. %hat is the height of the image of the flower& A) 5.:5 cm B) #5 cm C) 2.5 cm D) 1.6 cm ) :.5 cm Answer! A "ar! 1
9) An ob3ect 2.5 cm in height is placed :.5 cm in front of a concave spherical mirror with a focal length of 15.5 cm. %hat is the position of its image in relation to the mirror, and what are the characteristics of the image& A) 25.5 cm on the other side of mirror, real, 6.5 times bigger B) 15.5 cm on the other side of mirror, virtual, 15.5 times bigger C) 1:.5 cm on the same side of mirror, virtual, #.#8 times bigger D) 15.5 cm on the same side of mirror, real, 6.5 times bigger ) 25.5 cm on the other side of mirror, virtual, 8.5 times bigger Answer! "ar! 8
:) -he image of a plant is 2.5 cm from a concave spherical mirror having a radius of curvature of 15 cm. %here is the plant relative to the mirror& A) #.# cm in front of the mirror B) 2.2 cm in front of the mirror C) ;.5 cm in front of the mirror D) 1.5 cm in front of the mirror ) #5 cm in front of the mirror Answer! A "ar! 1
2 Copyright 4 #516 7earson ducation, 'nc.
;) A conve spherical mirror with a radius of 85 cm has a 2.5 cm tall ob3ect placed 155 cm in front of it. %hat is the position of the image relative to the mirror& A) #5 cm behind the mirror B) #8 cm behind the mirror C) 155 cm in front of the mirror D) #8 cm in front of the mirror ) #5 cm in front of the mirror Answer! A "ar! 1
15) An ob3ect +.2 mm tall is placed #8 cm from the verte of a conve spherical mirror. -he radius of curvature of the mirror has a magnitude of 8# cm. 0a)
11) A swimming pool is filled to a depth of #.5 m.
1#) A goldfish bowl is spherical, :.5 cm in radius. A goldfish is swimming +.5 cm from the wall of the bowl. %here does the fish appear to be to an observer outside& -he inde of refraction of water is 1.++. (eglect the effect of the glass wall of the bowl. A) +.+ cm inside the bowl B) +.; cm inside the bowl C) #.8 cm inside the bowl D) +.5 cm inside the bowl ) 1.9 cm inside the bowl Answer! C "ar! 1
1+) A fish appears to be #.55 m below the surface of a pond when viewed almost directly above by a fisherman. %hat is the actual depth of the fish& 0nwater @ 1.++) A) #.66 m B) 5.69 m C) 1.8 m D) 5.+: m Answer! A "ar! ;
8 Copyright 4 #516 7earson ducation, 'nc.
12) A fisherman in a stream +; cm deep looks downward into the water and sees a rock on the stream bed.
18) -he left>hand end of a glass rod is ground to a spherical surface. -he glass has inde of refraction 1.85. A small ob3ect 2.55 mm tall is placed on the ais of the rod, +9.5 cm to the left of the verte of the spherical surface. -he image is formed in the rod, 85.5 cm to the right of the verte. 0a) %hat is the magnitude of the radius of curvature of the spherical surface at the end of the rod& 0b) %hat is the height of the image& Answer! 0a) :.: cm 0b) +.65 mm "ar! 1
16) 'n the figure, the thin lens forms a real image of the ob3ect ;2.5 cm from the ob3ect. %hat is the focal length of the lens&
A) ##.5 cm B) #8.8 cm C) #9.8 cm D) 88.: cm ) :6.5 cm Answer! A "ar! 1
6 Copyright 4 #516 7earson ducation, 'nc.
19) 'n the figure, the image is viewed on a screen and is 1+.8 mm tall. %hat is the focal length of the lens&
A) ?12.6 cm B) >12.6 cm C) ?#5.2 cm D) >:;.+ cm ) ?1#2 cm Answer! C "ar! 1
1:) A thin converging lens is found to form an image of a distant building #2 cm from the lens. 'f an insect is now placed 16 cm from this lens, how far -< '($C- will its image be formed& A) 62 cm B) 9# cm C) +# cm D) ;6 cm ) 2: cm Answer! C "ar! 1
1;) An ob3ect is placed 15 cm from a conve lens of focal length #5 cm. %hat is the lateral magnification of the ob3ect& A) 5.85 B) 1.5 C) 1.8 D) #.5 ) #.8 Answer! D "ar! 1
9 Copyright 4 #516 7earson ducation, 'nc.
#5) 't is desired to pro3ect the image of an ob3ect four times its actual si*e using a lens of focal length #5 cm.
#1) %hen an ob3ect 1.18 cm tall is placed 1# cm from a lens, the lens produces an upright image of the ob3ect that is 8.98 cm tall. %hat is the focal length of the lens& A) #2 cm B) 1: cm C) 65 cm D) 18 cm ) ;.5 cm Answer! D "ar! 1
##) A 2.5>cm tall ob3ect is placed 65 cm away from a converging lens of focal length +5 cm. %hat are the nature and location of the image& -he image is A) real, #.8 cm tall, and +5 cm from the lens on the same side as the ob3ect. B) virtual, #.8 cm tall, and +5 cm from the lens on the side opposite the ob3ect. C) virtual, #.5 cm tall, and 18 cm from the lens on the side opposite the ob3ect. D) virtual, 2.5 cm tall, and 65 cm from the lens on the same side as the ob3ect. ) real, 2.5 cm tall, and 65 cm from the lens on the side opposite the ob3ect. Answer! "ar! 8
#+) A 2.5>cm tall ob3ect is placed 85.5 cm from a diverging lens having a focal length of magnitude #8.5 cm. %hat are the nature and location of the image& -he image is A) real, 2.5 cm tall, and #5 cm from the lens on the side opposite the ob3ect. B) virtual, 2.5 cm tall, and #5 cm from the lens on the side opposite the ob3ect. C) virtual, #.5 cm tall, and 15 cm from the lens on the side opposite the ob3ect. D) virtual, 1.+ cm tall, and 16.9 cm from the lens on the same side of the ob3ect. ) real, 1.+ cm tall, and 16.9 cm from the lens on the same side of the ob3ect. Answer! D "ar! 8
: Copyright 4 #516 7earson ducation, 'nc.
#2) An ob3ect is placed 155 cm in front of a lens of focal length #5 cm. A second lens is placed +8 cm beyond the first, this second lens having a focal length of :.5 cm. 'f the height of the ob3ect is 6.5 cm, what is the height of the final image& A) 1.8 cm B) 1# cm C) ;.5 cm D) +.5 cm ) 6.5 cm Answer! "ar! 1
#8) An ob3ect 1.:5 cm tall is placed 155 cm in front of a diverging lens having a focal length of magnitude #8 cm. A converging lens with a focal length of magnitude ++.++ cm is placed +5 cm past the first lens. %hat is the lateral magnification of this system of lenses& A) #.8 B) >#.8 C) >5.25 D) 1.5 ) 5.25 Answer! C "ar! 1
#6) An ob3ect 1.#8 cm tall is placed 155 cm in front of a conve lens with a focal length of magnitude 85 cm. A concave lens with a focal length of magnitude #5 cm is placed ;5 cm beyond the first lens. %here is the final image located& A) 15 cm in front of the second lens B) #5 cm past the second lens C) 19 cm past the second lens D) 15 cm past the second lens ) #5 cm in front of the second lens Answer! B "ar! 1
#9) An ob3ect is placed 155 cm in front of a diverging lens with a focal length of magnitude # 8 cm. A converging lens having a focal length of magnitude ++.++ cm is placed +5 cm past the first lens. %here is the final image formed& A) +5 cm after the second lens B) #5 cm in front of the first lens C) +.5 meters before the second lens D) 155 cm after the second lens ) +.5 cm before the second lens Answer! D "ar! 1
; Copyright 4 #516 7earson ducation, 'nc.
#:) An optical system comprises in turn, from left to right! an observer, a lens of focal length ?+5 cm, an erect ob3ect #5 mm high, and a conve mirror of radius :5 cm. -he ob3ect is between the lens and the mirror, #5 cm from the lens and 85 cm from the mirror. -he observer views the image that is formed first by reflection and then by refraction. %hat is the position of the final image, measured from the mirror&
A) ;5 cm B) 15# cm C) 112 cm D) 1#6 cm ) 1+: cm Answer! C "ar! 1
#;) 'n the figure, the radius of curvature of the curved part of the lens is #2.5 cm, and the refractive inde of the lens material is 1.985. %hat is the focal length of the lens&
A) ?+#.5 cm B) >+#.5 cm C) >16.5 cm D) ?1+.: cm ) >1+.: cm Answer! A "ar! 1
15 Copyright 4 #516 7earson ducation, 'nc.
+5) 'n the figure, the radius of curvature of the curved part of the lens is +8.5 cm, and the refractive inde of the lens material is 1.6#5. %hat is the focal length of the lens&
A) ?86.8 cm B) >86.8 cm C) ?#:.# cm D) ?#1.6 cm ) >#1.6 cm Answer! B "ar! 1
+1) A conve>concave thin lens is made with the radius of curvature of the conve surface being #8.5 cm and the concave surface 28.5 cm. 'f the glass used has inde of refraction 1.855, what is the focal length of this lens& A) >+#.5 cm B) +#.5 cm C) 11+ cm D) 69.8 cm ) >11+ cm Answer! C "ar! 1
+#) A double>conve thin lens is made of glass with an inde of refraction of 1.8#. -he radii of curvature of the faces of the lens are 65 cm and 9# cm. %hat is the focal length of the lens& A) 95 cm B) 6+ cm C) 98 cm D) 66 cm ) 8: cm Answer! B "ar! 1
++) A lens is made with a focal length of >25 cm using a material with inde of refraction 1.85. A second lens is made with the $A - as the first lens, but using a material having refractive inde of #.55. %hat is the focal length o f the second lens& A) >25 cm B) >:5 cm C) >8+ cm D) >#5 cm ) >+5 cm Answer! D "ar! 1
11 Copyright 4 #516 7earson ducation, 'nc.
+2) A double>concave lens has eEual radii of curvature of An ob3ect placed from the lens forms a virtual image from the lens. %hat is the inde of refraction of the lens material& A) 1.;5 B) 1.;: C) 1.:# D) 1.99 Answer! A "ar! 85?
+8) A thin double conve lens is to focus the image of an ob3ect onto a screen so that the image is life>si*ed. -he lens surfaces have eEual radii of curvature of 11# cm, and the refractive inde of the lens material is 1.855. 0a)
+6) A compound lens is made by 3oining the plane surfaces of two thin plano>conve lenses of different glasses. -he radius of curvature of each conve surface is :5 cm. -he indices of refraction of the two glasses are 1.85 and 1.65. %hat is the focal length of the compound lens& A) 69 B) 6; C) 91 D) 9+ ) 98 Answer! D "ar! 1
+9) A +8>mm camera eEuipped with a ;8 mm focal length lens is used to photograph a tree that is :.5 m tall. A +# mm high image of the tree on the film is needed. -he reEuired distance, between the tree and the camera lens, to take the photograph is closest to A) #2 m. B) #8 m. C) #6 m. D) #9 m. ) #; m. Answer! A "ar! 85?
1# Copyright 4 #516 7earson ducation, 'nc.
+:) 'n a +8.5>mm single lens refle camera 0$/), the distance from the lens to the film is varied in order to focus on ob3ects at varying distances. ver what distance range must a lens of 88>mm focal length vary if the camera is to be able to focus on ob3ects ranging in distance from infinity down to 5.65 m from the camera& A) 8.88 mm B) 2.22 mm C) 16.9 mm D) ##.# mm ) 9.99 mm Answer! A "ar! 85?
+;) A person=s eye lens is #.9 cm away from the retina. -his lens has a near point of #8 cm and a far point at infinity. 0a) %hat must the focal length of this lens be in order for an ob3ect placed at the near point of the eye to focus on the retina& 0b) %hat must the focal length of this lens be in o rder for an ob3ect placed at the far point of the eye to focus on the retina& Answer! 0a) #.2 cm 0b) #.9 cm "ar! 8
25) %hat is the focal length of the corrective contact lens needed by a nearsighted person whose far point is 65 cm& A) >65 cm B) >+5 cm C) ?+5 cm D) ?65 cm ) ?1+5 cm Answer! A "ar! 1
21) A nearsighted person has her distant vision corrected using a >#.5>diopter contact lens.
1+ Copyright 4 #516 7earson ducation, 'nc.
2#) -he near point of a person=s uncorrected eyes is 1#8.5 cm and the far point is at infinity. %hat is the focal length of a contact lens that will move the near point to #8.5 cm from this person=s eyes& A) >155 cm B) >+1.+ cm C) 15.# cm D) #5.: cm ) +1.+ cm Answer! "ar! 1
2+) -he near point of a farsighted person=s uncorrected eyes is :5 cm. %hat power contact lens should be used to move the near point to #8 cm from this person=s eyes& A) #.: diopters B) >#.: diopters C) >2.5 diopters D) >2.# diopters ) 2.# diopters Answer! A "ar! 1
22) %hat power contact lens must be used to correct the vision of a nearsighted person whose far point is 25 cm& A) #.8 diopters B) >#.8 diopters C) >+.6 diopters D) >2.5 diopters ) 2.5 diopters Answer! B "ar! 1
28) %hat is the uncorrected near point of a person who has a near point that is #8 cm from his eyes when he is wearing +.++>diopter contact lenses& A) 1.8 m B) 5.85 m C) 1.; m D) 5.98 m ) 5.65 m Answer! A "ar! 1
12 Copyright 4 #516 7earson ducation, 'nc.
26) A person can read the newspaper when it is held at 65 cm from his eyes. %hat should the focal length of his contact lenses be to allow him to read the newspaper comfortably at a distance of +5 cm& A) >+5 cm B) +5 cm C) >65 cm D) 65 cm ) ;5 cm Answer! D "ar! 1
29) A man is nearsighted and cannot see things clearly beyond 115from his eyes. %hat is the focal length of the contact lenses that will enable him to see very distant ob3ects clearly& A) 85 cm B) >85 cm C) >115 cm D) 115 cm ) >+5 cm Answer! C "ar! 8
2:) A nearsighted physicist cannot see things clearly beyond ; 5 cm from her eyes. %hat is the power of the contact lenses that will enable her to see very distant ob3ects clearly& A) 1.1 diopters B) >1.1 diopters C) >1.9 diopters D) >#.# diopters ) #.# diopters Answer! B "ar! 1
2;) A singer is farsighted and cannot see ob3ects clearly that are closer than :5.5 cm from his unaided eye. %hat is the refractive power of the contact lenses that will move his near point to a distance of #8.5 cm from his eye& A) #.98 diopters B) >#.98 diopters C) >2.9# diopters D) 2.9# diopters ) 9.55 diopters Answer! A "ar! 8
18 Copyright 4 #516 7earson ducation, 'nc.
85) A myopic 0nearsighted) dancer wears eyeglasses that allow him to have clear distant vision. -he power of the lenses of his eyeglasses is >+.55 diopters. %ithout eyeglasses, what is the far point of the dancer& A) 5.++ m B) 5.#8 m C) 5.19 m D) 5.2# m ) 5.85 m Answer! A "ar! 1#
81) A machinist with normal vision has a near point at #8 cm. -he machinist wears eyeglasses in order to do close work. -he power of the lenses is ?1.98 diopters. %ith these eyeglasses, what is the near point of the machinist& A) 19 cm B) 12 cm C) 15 cm D) #1 cm ) #2 cm Answer! A "ar! 12
8#) A person having a near point of #8 cm and a far point at infinity uses a converging lens of focal length 8.5 cm as a magnifying glass. %hat is the magnification if the person=s eye is relaed 0with the image at his far point)& Answer! 8.5 "ar! 1
8+) A magnifying lens has a focal length of 15 cm. A person has a near point of #8 cm and a far point at infinity. %hat is the angular magnification of the lens for that person when their eyes are focused at infinity& Answer! #.8 "ar! 1
82) %hat is the focal length of a magnifying glass that produces an angular magnification of 9.5 when used by a person with a near point at #: cm& A) #.5 cm B) +.5 cm C) 2.5 cm D) 8.5 cm ) 6.5 cm Answer! C "ar! 1
16 Copyright 4 #516 7earson ducation, 'nc.
88) %hat is the angular magnification of a magnifying glass of focal length 2.5 cm if the image is to be viewed by a relaed eye 0image at the far point) having a near point of #8 cm and a far point at infinity& A) #.5 B) +.5 C) +.6 D) 2.5 ) 6.+ Answer! "ar! 1
86) A magnifying glass uses a converging lens with a refractive power of #5 diopters. %hat is the magnification if the image is to be viewed by a relaed eye 0image at the far point) having a near point of #8 cm and a far point at infinity& A) 8.5 B) +.5 C) 2.5 D) 1.5 ) #.5 Answer! A "ar! 1
89) -he focal lengths of the ob3ective and the eyepiece of a microscope are 5.85 cm and #.5 cm, respectively, and their separation ad3usted for minimum eyestrain 0with the final image at the viewer=s far point) is 6.5 cm. -he near point o f the person using the microscope is #8 cm and the far point is infinity. 0a) 'f the microscope is focused on a small ob3ect, what is the distance between the ob3ect and the ob3ective lens& 0b) 'f the microscope is focused on a small ob3ect, what is its final magnification& Answer! 0a) 5.89 cm 0b) >155 "ar! 1
8:) -he distance between the ob3ect and the eyepiece of a compound microscope is #8.5 cm. -he focal length of its ob3ective lens is 5.#55 c m and the eyepiece has a focal length of #.65 cm. A person with a near point of #8.5 cm and a far point at infinity is using the microscope. 0a) %hat is the angular magnification obtainable using the eyepiece alone as a magnifying lens if the final image is at the person=s far point& 0b) %hat is the total magnification of the microscope when used by the person of normal eyesight& Answer! 0a) ;.6# 0b) >1595 "ar! 1
19 Copyright 4 #516 7earson ducation, 'nc.
8;) -he focal lengths of the ob3ective and eyepiece in a compound microscope are 5.:5 cm and #.8 cm, respectively. -he image formed by the ob3ective is 16 cm from it and the final image is #8 cm from the eye. %hat is the total overall magnification of the microscope& A) >1; B) >11 C) >#.5 D) >155 ) >#55 Answer! "ar! 1
65) -he focal lengths of the ob3ective and the eyepiece in a microscope are 5.#; cm and #.85 cm, respectively. An ob3ect is placed at 5.+5 cm from the ob3ective lens and the image of this ob3ect is viewed with the eyepiece ad3usted for minimum eyestrain 0with the eye focused at the far point). -he near point of the person using the microscope is #8 cm and the far point is at infinity. %hat is the final overall magnification of the microscope& A) >1;5 B) >#25 C) >+55 D) >+#5 ) >295 Answer! C "ar! 1
61) -he distance between the ob3ect and the eyepiece of a compound microscope is 1:.5 cm. -he focal length of its ob3ective lens is 5.:5 c m and the eyepiece has a focal length of #.+ cm. -he near>point distance of the person using the microscope is #8.5 cm. %hat is the total overall magnification of the microscope& A) >1#5 B) >1:2 C) >#55 D) >+65 ) >2:5 Answer! C "ar! 1
6#) -he focal lengths of the ob3ective and the eyepiece in a microscope are 5.#;5 cm and #.85 cm, respectively. An ob3ect is placed 5.+55 cm from the ob3ective. -he image of this ob3ect is viewed with the eyepiece ad3usted for minimum eyestrain 0image at the far point of the eye) for a person with normal vision. %hat is the distance between the ob3ective and the eyepiece& A) ;.:8 cm B) 15.1 cm C) 15.2 cm D) 11.# cm ) 11.8 cm Answer! D "ar! 1
6+) -he ob3ective and the eyepiece of a microscope have focal lengths of 2.55 mm and #8.5 mm, 1: Copyright 4 #516 7earson ducation, 'nc.
respectively. -he ob3ective produces a real image +5 times the si*e of the ob3ect. -he final image is viewed at infinity, and the near point of the microscope user is at #8.5 cm. %hat is the distance between the ob3ect and the focal point of the ob3ective& A) 5.1+ mm B) 5.1: mm C) 5.#+ mm D) 5.#: mm ) 5.++ mm Answer! A "ar! 1
62) -he eyepiece of a compound microscope has a focal length of #.85 cm and the ob3ective has a focal length of 1.65 cm. -he two lenses are separated by 18.5 cm. -he microscope is used by a person with normal eyes 0near point at #8 cm). %hat is the angular magnification of the microscope& A) 9: B) ;2 C) 1;8 D) #+2 ) 1#8 Answer! A "ar! 85?
68) ou have available lenses of focal lengths #.5 cm, 2.5 cm, :.5 cm, and 16.5 cm. 0a) 'f you were to use any two of these lenses to build a telescope, what is the maimum magnification you could achieve& 0b) 'f you were to use any two of these lenses to build a telescope, what is the lens separation for the maimum magnification telescope& Answer! 0a) :.5 0b) 1: cm "ar! 1
66) -he ob3ective lens of a refracting telescope has a focal length of 65 cm and the eyepiece a focal length of :.5 cm. %hat is the angular magnification of the telescope& A) +2 B) 2:5 C) 6: D) 5.1+ ) 9.8 Answer! "ar! 1
1; Copyright 4 #516 7earson ducation, 'nc.
69) An astronomical telescope has an ob3ective of diameter #5 cm with a focal length of 1:5 cm. -he telescope is used with an eyepiece of focal length +5 mm. %hat is the angular magnification of this telescope& A) +65 B) 65 C) 825 D) 6 ) 1:5 Answer! B "ar! 1
6:) -he angular magnification of a refracting telescope is 2 5 . %hen the ob3ect and final image are both at infinity, the distance between the eyepiece and the ob3ective is 12+.8 cm. -he telescope is used to view a distant radio tower. -he real image of the tower, formed by the ob3ective, is 6.5 mm in height. -he focal point of the eyepiece is positioned at the real image. %hat is the focal length of the ob3ective lens& A) 1+9 cm B) 1+: cm C) 1+; cm D) 125 cm ) 121 cm Answer! D "ar! 1
6;) -he angular magnification of a refracting telescope is 2 5 . %hen the ob3ect and final image are both at infinity, the distance between the eyepiece and the ob3ective is 12+.8 cm. -he telescope is used to view a distant radio tower. -he real image of the tower, formed by the ob3ective, is 6.5 mm in height. -he focal point of the eyepiece is positioned at the real image. %hat is the angle subtended by the final image of the tower. A) 5.18 rad B) 5.19 rad C) 5.1; rad D) 5.#1 rad ) 5.#+ rad Answer! B "ar! 1
#5 Copyright 4 #516 7earson ducation, 'nc.
95) -he ob3ective and the eyepiece of a refracting astronomical telescope have focal lengths of +#5 cm and 2.5 cm, respectively. -he telescope is used to view (eptune and the final image is set at infinity. -he diameter of (eptune is 2.;6 F 159 m and the distance from the earth at the time of observation is 2.2 F 151# m. %hat is the angle 0in mrad) subtended by the final telescopic image of (eptune& A) 5.;5 mrad B) 1.1 mrad C) 1.+ mrad D) 1.8 mrad ) 1.9 mrad Answer! A "ar! 1
#1 Copyright 4 #516 7earson ducation, 'nc.
