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Exam 27: Optical Instruments

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Question 31

Multiple Choice

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

F) A) and B)
G) C) and D)

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Question 32

Multiple Choice

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A nearsighted person wears contact lenses having a power of -0.15 diopters.What is the person's uncorrected far point?

A) 1.5 m
B) 3.3 m
C) 6.0 m
D) 6.7 m

E) A) and D)
F) C) and D)

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Question 33

Multiple Choice

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Olga is nearsighted and cannot see things beyond 90 cm cm from her eyes.What is the refractive power of the contact lenses that will enable her to comfortably see distant buildings clearly?

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.The magnitude of the overall magnification of the microscope is closest to

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?

A refracting telescope has a magnification M.If the focal length of the objective lens is doubled and the eyepiece focal length is halved,what is the new magnification?

What is the focal length of a contact lens that will allow a person with a near point of 125 cm to read a physics book held 25.0 cm from his eyes?

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

A nearsighted person has a far point that is 4.2 m from his eyes.What focal length lenses must he use in his contact lenses to allow him to focus on very distant mountains?

A telescope has an angular magnification of 250 when used with a 20 mm eyepiece.What is the focal length of the objective lens?

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?

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?

A simple refracting telescope provides large magnification by employing

A lens of focal length 40 mm is used as a magnifier.The object being viewed is 5.3 mm long,and is positioned at the focal point of the lens.The user of the magnifier has a near point at 25 cm.What is the angular magnification of the magnifier?

What is the angular magnification of a magnifying glass of focal length 4.0 cm if the image is to be viewed by a relaxed eye having a near point of 25 cm?

The objective lens 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,with the final image viewed at infinity.The near point of the microscope user is at 25 cm.What is the distance between the objective lens and the real image that it produces?

A person's eye lens is 2.8 cm from the retina,and his near point is at 25 cm.What must be the focal length of his eye lens so that an object at the far point of the eye will focus on the retina?

A simple compound microscope normally uses

If the back of a person's eye is too close to the lens,this person is suffering from

A farsighted boy has a near point at 2.3 m and requires contact lenses to correct his vision to the normal near point.What is the correct choice of lens power for the contact lenses?