Question 1

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 2

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 angle subtended by the final image of the tower.

Accepted Answer

A)  0.15 rad 
B)  0.17 rad 
C)  0.19 rad 
D)  0.21 rad 
E)  0.23 rad

Question 3

An object is placed 100 cm in front of a lens of focal length 20 cm.A second lens is placed 35 cm beyond the first,this second lens having a focal length of 8.0 cm.If the height of the object is 6.0 cm,what is the height of the final image?

Accepted Answer

A)  1.5 cm 
B)  12 cm 
C)  9.0 cm 
D)  3.0 cm 
E)  6.0 cm

Question 4

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 5

The image of a plant is 4.0 cm from a concave spherical mirror having a radius of curvature of 10 cm. Where is the plant relative to the mirror?

Accepted Answer

A)  2.2 cm in front of the mirror 
B)  4.4 cm in front of the mirror 
C)  9.0 cm in front of the mirror 
D)  1.0 cm in front of the mirror 
E)  20 cm in front of the mirror

Question 6

A double-concave lens has equal radii of curvature of 15.1 cm.An object placed 14.2 cm from the lens forms a virtual image 5.29 cm from the lens.What is the index of refraction of the lens material?

Accepted Answer

A)  1.90 
B)  1.98 
C)  1.82 
D)  1.77

Question 7

A convex spherical mirror with a focal length of magnitude 25 cm has a 4.0-cm tall flower placed 100 cm in front of it. What is the height of the image of the flower?

Accepted Answer

A)  0.80 cm 
B)  20 cm 
C)  4.0 cm 
D)  1.6 cm 
E)  8.0 cm

Question 8

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 9

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 10

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

Question 11

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 12

A simple refracting telescope provides large magnification by employing

Accepted Answer

A)  a short focal length objective and a short focal length eyepiece. 
B)  a short focal length objective and a long focal length eyepiece. 
C)  a long focal length objective and a short focal length eyepiece. 
D)  a long focal length objective and a long focal length eyepiece.

Question 13

It is desired to project the image of an object four times its actual size using a lens of focal length 20 cm.How far from the lens should the object be placed?

Accepted Answer

A)  100 cm 
B)  80 cm 
C)  4.0 cm 
D)  25 cm 
E)  5.0 cm

Question 14

An astronomical telescope has an objective of diameter 20 cm with a focal length of 180 cm.The telescope is used with an eyepiece of focal length 30 mm.What is the angular magnification of this telescope?

Accepted Answer

A)  360 x 
B)  60 x 
C)  540 x 
D)  6 x 
E)  180 x

Question 15

An optical system comprises in turn,from left to right: an observer,a lens of focal length +30 cm,an erect object 20 mm high,and a convex mirror of radius 80 cm.The object is between the lens and the mirror,20 cm from the lens and 50 cm from the mirror.The observer views the image that is formed first by reflection and then by refraction.What is the position of the final image,measured from the mirror?

Accepted Answer

A)  90 cm 
B)  102 cm 
C)  114 cm 
D)  126 cm 
E)  138 cm

Question 16

A 4.0-cm tall object is placed 60 cm away from a converging lens of focal length 30 cm.What are the nature and location of the image? The image is

Accepted Answer

A)  real, 2.5 cm tall, and 30 cm from the lens on the same side as the object. 
B)  virtual, 2.5 cm tall, and 30 cm from the lens on the side opposite the object. 
C)  virtual, 2.0 cm tall, and 15 cm from the lens on the side opposite the object. 
D)  virtual, 4.0 cm tall, and 60 cm from the lens on the same side as the object. 
E)  real, 4.0 cm tall, and 60 cm from the lens on the side opposite the object.

Question 17

A ray of light goes from one transparent material into another,as shown in the figure.What can you conclude about the indices of refraction of these two materials?

Accepted Answer

A)  n1 ≥ n2 
B)  n1 > n2 
C)  n1 = n2 
D)  n2 ≥ n1 
E)  n2 > n1

Question 18

A convex-concave thin lens is made with the radius of curvature of the convex surface being 25.0 cm and the concave surface 45.0 cm.If the glass used has index of refraction 1.500,what is the focal length of this lens?

Accepted Answer

A)  -32.0 cm 
B)  32.0 cm 
C)  113 cm 
D)  67.5 cm 
E)  -113 cm

Question 19

A 4.0-cm tall object is placed 50.0 cm from a diverging lens having a focal length of magnitude 25.0 cm.What are the nature and location of the image? The image is

Accepted Answer

A)  real, 4.0 cm tall, and 20 cm from the lens on the side opposite the object. 
B)  virtual, 4.0 cm tall, and 20 cm from the lens on the side opposite the object. 
C)  virtual, 2.0 cm tall, and 10 cm from the lens on the side opposite the object. 
D)  virtual, 1.3 cm tall, and 16.7 cm from the lens on the same side of the object. 
E)  real, 1.3 cm tall, and 16.7 cm from the lens on the same side of the object.

Question 20

An object 1.80 cm tall is placed 100 cm in front of a diverging lens having a focal length of magnitude 25 cm.A converging lens with a focal length of magnitude 33.33 cm is placed 30 cm past the first lens.What is the lateral magnification of this system of lenses?

Accepted Answer

A)  2.5 
B)  -2.5 
C)  -0.40 
D)  1.0 
E)  0.40

Exam 33: Ray Optics