Question 1

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 (image at the far point)having a near point of 25 cm and a far point at infinity?

Accepted Answer

A)  2.0 x 
B)  3.0 x 
C)  3.6 x 
D)  4.0 x 
E)  6.3 x

Question 2

The distance between the object and the eyepiece of a compound microscope is 25.0 cm.The focal length of its objective lens is 0.200 cm and the eyepiece has a focal length of 2.60 cm.A person with a near point of 25.0 cm and a far point at infinity is using the microscope.
(a)What is the angular magnification obtainable using the eyepiece alone as a magnifying lens if the final image is at the person's far point?
(b)What is the total magnification of the microscope when used by the person of normal eyesight?

Accepted Answer

The answer of The distance between the object and the...

Question 3

What is the focal length of a magnifying glass that produces an angular magnification of 7.0 x when used by a person with a near point at 28 cm?

Accepted Answer

A)  2.0 cm 
B)  3.0 cm 
C)  4.0 cm 
D)  5.0 cm 
E)  6.0 cm

Question 4

As you walk away from a vertical plane mirror,your image in the mirror

Accepted Answer

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 image to a real image as you pass the focal point. 
E)  decreases in height.

Question 5

The angular magnification of a refracting telescope is 40 x.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.What is the focal length of the objective lens?

Accepted Answer

A)  137 cm 
B)  138 cm 
C)  139 cm 
D)  140 cm 
E)  141 cm

Question 6

In the figure,the radius of curvature of the curved part of the lens is 35.0 cm,and the refractive index of the lens material is 1.620.What is the focal length of the lens?

Accepted Answer

A)  +56.5 cm 
B)  -56.5 cm 
C)  +28.2 cm 
D)  +21.6 cm 
E)  -21.6 cm

Question 7

A swimming pool is filled to a depth of 2.0 m.How deep does the pool appear to be from above the water,which has an index of refraction of 1.33?

Accepted Answer

A)  1.5 m 
B)  1.33 m 
C)  2.5 m 
D)  3.0 m 
E)  4.0 cm

Question 8

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 +1.75 diopters.With these eyeglasses,what is the near point of the machinist?

Accepted Answer

A)  17 cm 
B)  14 cm 
C)  10 cm 
D)  21 cm 
E)  24 cm

Question 9

The focal lengths of the objective 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 (with the eye focused at the far point).The near point of the person using the microscope is 25 cm and the far point is at infinity.What is the final overall magnification of the microscope?

Accepted Answer

A)  -190 x 
B)  -240 x 
C)  -300 x 
D)  -320 x 
E)  -470 x

Question 10

What is the uncorrected near point of a person who has a near point that is 25 cm from his eyes when he is wearing 3.33-diopter contact lenses?

Accepted Answer

A)  1.5 m 
B)  0.50 m 
C)  1.9 m 
D)  0.75 m 
E)  0.60 m

Question 11

The focal lengths of the objective and the eyepiece in a microscope are 0.290 cm and 2.50 cm,respectively.An object is placed 0.300 cm from the objective.The image of this object is viewed with the eyepiece adjusted for minimum eyestrain (image at the far point of the eye)for a person with normal vision.What is the distance between the objective and the eyepiece?

Accepted Answer

A)  9.85 cm 
B)  10.1 cm 
C)  10.4 cm 
D)  11.2 cm 
E)  11.5 cm

Question 12

A concave spherical mirror with a radius of 20 cm creates a real image 30 cm from the mirror.How far is the object from the mirror?

Accepted Answer

A)  50 cm 
B)  20 cm 
C)  15 cm 
D)  7.5 cm 
E)  5.0 cm

Question 13

An object 1.25 cm tall is placed 100 cm in front of a convex lens with a focal length of magnitude 50 cm.A concave lens with a focal length of magnitude 20 cm is placed 90 cm beyond the first lens.Where is the final image located?

Accepted Answer

A)  10 cm in front of the second lens 
B)  20 cm past the second lens 
C)  17 cm past the second lens 
D)  10 cm past the second lens 
E)  20 cm in front of the second lens

Question 14

In the figure,the image is viewed on a screen and is 13.5 mm tall.What is the focal length of the lens?

Accepted Answer

A)  +14.6 cm 
B)  -14.6 cm 
C)  +20.4 cm 
D)  -89.3 cm 
E)  +124 cm

Question 15

A magnifying lens has a focal length of 10 cm.A person has a near point of 25 cm and a far point at infinity.What is the angular magnification of the lens for that person when their eyes are focused at infinity?

Accepted Answer

The answer of A magnifying lens has a focal length...

Question 16

A thin double convex lens is to focus the image of an object onto a screen so that the image is life-sized.The lens surfaces have equal radii of curvature of 112 cm,and the refractive index of the lens material is 1.500.
(a)How far from the lens should the screen be placed?
(b)How far is the screen from the object?

Accepted Answer

The answer of A thin double convex lens is to...

Question 17

A man is nearsighted and cannot see things clearly beyond 110from his eyes.What is the focal length of the contact lenses that will enable him to see very distant objects clearly?

Accepted Answer

A)  50 cm 
B)  -50 cm 
C)  -110 cm 
D)  110 cm 
E)  -30 cm

Question 18

A magnifying glass uses a converging lens with a refractive power of 20 diopters.What is the magnification if the image is to be viewed by a relaxed eye (image at the far point)having a near point of 25 cm and a far point at infinity?

Accepted Answer

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

Question 19

A person can read the newspaper when it is held at 60 cm from his eyes.What should the focal length of his contact lenses be to allow him to read the newspaper comfortably at a distance of 30 cm?

Accepted Answer

A)  -30 cm 
B)  30 cm 
C)  -60 cm 
D)  60 cm 
E)  90 cm

Question 20

A singer is farsighted and cannot see objects clearly that are closer than 80.0 cm from his unaided eye.What is the refractive power of the contact lenses that will move his near point to a distance of 25.0 cm from his eye?

Accepted Answer

A)  2.75 diopters 
B)  -2.75 diopters 
C)  -4.72 diopters 
D)  4.72 diopters 
E)  7.00 diopters

Exam 34: Geometric Optics

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 (image at the far point) having a near point of 25 cm and a far point at infinity?