Question 1

A goldfish bowl is spherical,8.0 cm in radius.A goldfish is swimming 3.0 cm from the wall of the bowl.Where does the fish appear to be to an observer outside? The index of refraction of water is 1.33.Neglect the effect of the glass wall of the bowl.

Accepted Answer

A)  3.3 cm inside the bowl 
B)  3.9 cm inside the bowl 
C)  2.5 cm inside the bowl 
D)  3.0 cm inside the bowl 
E)  1.7 cm inside the bowl

Question 2

A double-convex thin lens is made of glass with an index of refraction of 1.52.The radii of curvature of the faces of the lens are 60 cm and 72 cm.What is the focal length of the lens?

Accepted Answer

A)  70 cm 
B)  63 cm 
C)  75 cm 
D)  66 cm 
E)  58 cm

Question 3

The objective and the eyepiece of a microscope have focal lengths of 4.00 mm and 25.0 mm,respectively.The objective produces a real image 30 times the size of the object.The final image is viewed at infinity,and the near point of the microscope user is at 25.0 cm.What is the distance between the object and the focal point of the objective?

Accepted Answer

A)  0.13 mm 
B)  0.18 mm 
C)  0.23 mm 
D)  0.28 mm 
E)  0.33 mm

Question 4

An object 4.0 cm in height is placed 8.0 cm in front of a concave spherical mirror with a focal length of 10.0 cm.What is the position of its image in relation to the mirror,and what are the characteristics of the image?

Accepted Answer

A)  40.0 cm on the other side of mirror, real, 6.0 times bigger 
B)  10.0 cm on the other side of mirror, virtual, 10.0 times bigger 
C)  18.0 cm on the same side of mirror, virtual, 2.25 times bigger 
D)  10.0 cm on the same side of mirror, real, 6.0 times bigger 
E)  40.0 cm on the other side of mirror, virtual, 5.0 times bigger

Question 5

The focal lengths of the objective and eyepiece in a compound microscope are 0.80 cm and 2.5 cm,respectively.The image formed by the objective is 16 cm from it and the final image is 25 cm from the eye.What is the total overall magnification of the microscope?

Accepted Answer

A)  -19 x 
B)  -11 x 
C)  -2.0 x 
D)  -100 x 
E)  -200 x

Question 6

The objective lens of a refracting telescope has a focal length of 60 cm and the eyepiece a focal length of 8.0 cm.What is the angular magnification of the telescope?

Accepted Answer

A)  34 x 
B)  480 x 
C)  68 x 
D)  0.13 x 
E)  7.5 x

Question 7

You have available lenses of focal lengths 2.0 cm,4.0 cm,8.0 cm,and 16.0 cm.
(a)If you were to use any two of these lenses to build a telescope,what is the maximum magnification you could achieve?
(b)If you were to use any two of these lenses to build a telescope,what is the lens separation for the maximum magnification telescope?

Accepted Answer

The answer of You have available lenses of focal lengths...

Question 8

Which statements are true about a VIRTUAL image? (There may be more than one correct choice.)

Accepted Answer

A)  Its location can be calculated, but it cannot be viewed directly by your eye without using auxiliary lenses. 
B)  It cannot be photographed. 
C)  It cannot be viewed on a screen. 
D)  A plane mirror always forms a virtual image. 
E)  A concave lens always forms a virtual image.

Question 9

A convex lens has a focal length f.An object is placed between infinity and 2f from the lens along a line perpendicular to the center of the lens.The image is located at what distance from the lens?

Accepted Answer

A)  farther than 2f 
B)  2f 
C)  between f and 2f 
D)  f 
E)  between the lens and f

Question 10

A nearsighted physicist cannot see things clearly beyond 90 cm from her eyes.What is the power of the contact lenses that will enable her to see very distant objects clearly?

Accepted Answer

A)  1.1 diopters 
B)  -1.1 diopters 
C)  -1.7 diopters 
D)  -2.2 diopters 
E)  2.2 diopters

Question 11

A nearsighted person has her distant vision corrected using a -2.0-diopter contact lens.Her uncorrected near point is 15 cm.What is her near point using this lens if the lens is 2.0 cm from the eye?

Accepted Answer

A)  17 cm 
B)  20 cm 
C)  13 cm 
D)  18 cm 
E)  15 cm

Question 12

The focal lengths of the objective and the eyepiece of a microscope are 0.50 cm and 2.0 cm,respectively,and their separation adjusted for minimum eyestrain (with the final image at the viewer's far point)is 6.0 cm.The near point of the person using the microscope is 25 cm and the far point is infinity.
(a)If the microscope is focused on a small object,what is the distance between the object and the objective lens?
(b)If the microscope is focused on a small object,what is its final magnification?

Accepted Answer

The answer of The focal lengths of the objective and...

Question 13

The left-hand end of a glass rod is ground to a spherical surface.The glass has index of refraction 1.50.A small object 4.00 mm tall is placed on the axis of the rod,37.0 cm to the left of the vertex of the spherical surface.The image is formed in the rod,50.0 cm to the right of the vertex.
(a)What is the magnitude of the radius of curvature of the spherical surface at the end of the rod?
(b)What is the height of the image?

Accepted Answer

The answer of The left-hand end of a glass rod...

Question 14

A person having a near point of 25 cm and a far point at infinity uses a converging lens of focal length 5.0 cm as a magnifying glass.What is the magnification if the person's eye is relaxed (with the image at his far point)?

Accepted Answer

The answer of A person having a near point of...

Question 15

A myopic (nearsighted)dancer wears eyeglasses that allow him to have clear distant vision.The power of the lenses of his eyeglasses is -3.00 diopters.Without eyeglasses,what is the far point of the dancer?

Accepted Answer

A)  0.33 m 
B)  0.25 m 
C)  0.17 m 
D)  0.42 m 
E)  0.50 m

Question 16

An object 3.4 mm tall is placed 25 cm from the vertex of a convex spherical mirror.The radius of curvature of the mirror has a magnitude of 52 cm.
(a)How far is the image from the vertex of the mirror?
(b)What is the height of the image?

Accepted Answer

The answer of An object 3.4 mm tall is placed...

Question 17

What is the focal length of the corrective contact lens needed by a nearsighted person whose far point is 60 cm?

Accepted Answer

A)  -60 cm 
B)  -30 cm 
C)  +30 cm 
D)  +60 cm 
E)  +130 cm

Question 18

A fish appears to be 2.00 m below the surface of a pond when viewed almost directly above by a fisherman.What is the actual depth of the fish? (nwater = 1.33)

Accepted Answer

A)  2.66 m 
B)  0.67 m 
C)  1.5 m 
D)  0.38 m

Question 19

A lens is made with a focal length of -40 cm using a material with index of refraction 1.50.A second lens is made with the SAME GEOMETRY as the first lens,but using a material having refractive index of 2.00.What is the focal length of the second lens?

Accepted Answer

A)  -40 cm 
B)  -80 cm 
C)  -53 cm 
D)  -20 cm 
E)  -30 cm

Question 20

How far are you from your image when you stand 0.750 m in front of a vertical plane mirror?

Accepted Answer

A)  0.375 m 
B)  0.750 m 
C)  1.50 m 
D)  3.00 m

Exam 34: Geometric Optics