Exam 27: Optical Instruments

A farsighted person cannot see clearly objects that are closer to her eyes than 60.0 cm.Which one of the following combinations represents the correct focal length and the refractive power of the contact lenses that will enable her to comfortably see the objects at a distance of 25.0 cm from her eyes?

The near point of a farsighted person is 100 cm.She places reading glasses very close to her eyes,and with them she can comfortably read a book at a distance of 25 cm.What is the power of the lenses in her reading glasses?

The focal lengths of the objective lens and the eyepiece in a microscope are 0.29 cm and 2.50 cm,respectively.An object is placed at 0.30 cm from the objective lens and the image of this object is viewed with the eyepiece adjusted for minimum eyestrain for persons with a near point of 25 cm.The magnitude of the final overall magnification of the microscope is closest to

Chromatic aberration in lenses is due to the

A very delicate sample is placed 0.150 cm from the objective lens of a microscope.The focal length of the objective is 0.140 cm,and that of the eyepiece is 1.0 cm.The near-point distance of the person using the microscope is 25.0 cm.The magnitude of the final magnification of the microscope is closes to

You have available lenses of focal lengths 2.0 cm,4.0 cm,8.0 cm,and 16.0 cm.If you could use any two of these lenses to build a telescope,what is the maximum magnification you could achieve for comfortable viewing of a planet?

The focal length of the lens of a simple digital camera is 40 mm,and it is originally focused on a person 25 m away.In what direction must the lens be moved to change the focus of the camera to a person 4.0 m away?

A nearsighted person cannot see objects beyond 80 cm from his eyes.Which one of the following combinations represents the correct focal length and the refractive power of the contact lenses that will enable him to comfortably see the distant objects clearly?

You have available lenses of focal lengths 2.0 cm,4.0 cm,8.0 cm,and 16 cm.If you could use any two of these lenses to build a telescope,what is the lens separation for the telescope to provide the maximum magnification for comfortable viewing of a planet?

To maximize the magnification of a refracting telescope,what lenses should you choose?

The length of the telescope is 1.60 m,and it has a magnification of 60.0.What is the focal length of the objective lens?

What is the uncorrected near point of a farsighted person who can comfortably read a newspaper held 25 cm from his eyes when he wears +3.33-diopter contact lenses?

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 × 10⁷ m,and its distance from Earth at the time of observation is 4.4 × 10¹² m.What is the angle (in milliradians)subtended by the final telescopic image of Neptune?

The focal length of a converging lens is 10 cm.What is the angular magnification of this lens if the image is viewed by a relaxed eye with a near point of 25 cm?

You are given two converging lenses to build a compound microscope.Lens A has focal length 0.50 cm and lens B has focal length of 3.0 cm.Which one of the two lenses would you use for the objective?

The power of a lens is 4.0 diopters and its diameter is 5.0 cm.What is the focal length of this lens?

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?

The objective lens of a refracting astronomical telescope has a focal length of 60 cm,and the eyepiece has a focal length of 2.0 cm.How far apart should the lenses be placed in order to form a final image at infinity?

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?

Farsightedness can usually be corrected with