Chapter 26: Reflection, Refraction and Geometrical Optics
Physlet® Problems



1.  

The principal rays emanating from an object are drawn. You can click-drag the tip of the arrow-shaped object inside the pink box (the position is given in centimeters and the angle is given in degrees). A red curtain covers part of the animation and therefore you cannot see the rays in that region.  What kind of mirror is covered by the curtain?  Start
A concave mirror.
A convex mirror. 
Cannot determine.
A plane mirror.

2.  

The principal rays emanating from an object are drawn. You can click-drag the tip of the arrow-shaped object inside the pink box (the position is given in centimeters and the angle is given in degrees). A red curtain covers part of the animation and therefore you cannot see the rays in that region.  What kind of mirror is covered by the curtain?  Start
A plane mirror.
A concave mirror.
A convex mirror.
Cannot determine.

3.  

The principal rays emanating from an object are drawn. You can click-drag the tip of the arrow-shaped object inside the pink box (the position is given in centimeters and the angle is given in degrees). A red curtain covers part of the animation and therefore you cannot see the rays in that region.  What kind of mirror is covered by the curtain?  Start

Interactive Hint

Remove the curtain to see the rays. Remove curtain

A plane mirror.
A concave mirror.
A convex mirror. 
Cannot determine.

4.  

A point source is located to the left of a mirror (the position is given in meters and the angle is given in degrees).  The animation is drawn using the small angle approximation. You can drag this point source to any position and spread out or narrow the beam.  Find the focal length of the mirror.  Start
1.0 m.
1.3 m.
1.6 m.
1.9 m.

5.  

An arrow shaped object is located to the left of a mirror.  The animation is drawn using the small angle approximation. You can drag the tip of this object to any position (the position is given in meters and the angle is given in degrees).  Find the focal length of the mirror.  Start

Interactive Hint

More Help.

1.5 m.
1.0 m.
-1.0 m.
-1.5 m.

6.  

A beam of light is incident upon a mirror.  The animation is drawn using the small angle approximation. You can click-drag both the position and angle of this beam (the position is given in meters and the angle is given in degrees).  Find the focal length of the mirror.  Start
0.5 m.
0.75 m.
1.0 m.
1.25 m.

7.  

The principal rays emanating from an object are drawn as you click-drag the top of the arrow-shaped object in the animation (the position is given in centimeters and the angle is given in degrees).  Which statement is true?  Start  

Note: this simulation uses the small angle approximation---the rays from an object hit the mirror close to the central axis---and therefore the rays in the animation do not reflect from the mirror itself, but instead from where the mirror would be in the small angle approximation.
The magnification changes sign when the tip of the arrow is dragged below the principal axis.
Virtual images always invert the object.
Light rays leaving the tip of the arrow always pass through the image. 
The image of an object that is not on the principal axis can never overlap the object.

8.  

A  light beam source is incident on a substance of unknown index of refraction.  You can click-drag both the position and the ray angle of the beam.  Angle measurements are displayed in the yellow message box if click-drag away from the source (the position is given in centimeters and the angle is given in degrees). What is the unknown index?     Start
n=0.6.
n=1.0.
n=1.4.
n=1.8.

9.  

A  light beam source is fixed inside a substance that has a width of  10 cm and an unknown index of refraction. A red curtain covers the second interface with the air and therefore you cannot see the rays in that region. You can click-drag the ray angle of the beam (when you click on the source a green dot appears).  Angle measurements are displayed in the yellow message box if click-drag away from the source (the position is given in centimeters and the angle is given in degrees). What is the unknown index?     Start
n=0.6.
n=1.0.
n=1.4.
n=1.8.

10.  

A source of light is embedded in a substance of unknown index of refraction.  Angle measurements are displayed in the yellow message box if click-drag near a ray (the position is given in meters and the angle is given in degrees). Where is the image located as seen by someone looking into the substance from the right?   Start
The image is at the point (0.8 m, 0 m).
The image is at the point (1.0 m, 0 m).
The image is at the point (1.2 m, 0 m).
The image is at the point (1.4 m, 0 m).

11.  

A source of light is embedded in a substance of unknown index of refraction. What is the speed of light in the blue medium if the black medium is air? Angle measurements are displayed in the yellow message box if click-drag near a ray (the position is given in centimeters and the angle is given in degrees).  Start
3.0x108 m/s.
0.7x108 m/s.
2.7x108 m/s.
1.7x108 m/s.

12.  

A light source is embedded inside an unknown substance.  You can click-drag both the position and the ray-angle for this source (the position is given in centimeters and the angle is given in degrees).  What is the index of refraction of the substance?  Start
n=1.2.
n=1.6.
n=2.0.
n=2.4.

13.  

The principal rays emanating from an object are drawn. You can click-drag the tip of the arrow-shaped object inside the pink box (the position is given in centimeters and the angle is given in degrees). A red curtain covers part of the animation and therefore you cannot see the rays in that region.  What kind of lens is covered by the curtain?  Start
A converging lens.
A diverging lens.
Cannot determine.

14.  

The principal rays emanating from an object are drawn. You can click-drag the tip of the arrow-shaped object inside the pink box (the position is given in centimeters and the angle is given in degrees). A red curtain covers part of the animation and therefore you cannot see the rays in that region.  What kind of lens is covered by the curtain?  Start
A converging lens.
A diverging lens.
Cannot determine.

15.  

A light source is located to the left of a lens.  You can click-drag the lens to any position (the position is given in meters and the angle is given in degrees).  Find the focal length of the lens.  Start

Interactive Hint

More Help.
0.7 m.
1.0 m.
1.3 m.
1.6 m.

16.  

An arrow shaped object is located to the left of a lens.  The animation is drawn assuming a thin lens and the small angle approximation. You can drag this point object to any position (the position is given in meters and the angle is given in degrees).  Find the focal length of the lens.  Start

Interactive Hint

More Help.
-0.5 m.
-0.8 m.
-1.1 m.
-1.4 m.

17.  

You are trying to focus your camera so as to get a picture of a near and a far object.  The animation is drawn assuming a thin lens and the small angle approximation. You can focus the camera by moving the lens but you cannot change your position nor can you move the objects.  That is, you can move (click-drag in the simulation) the lens in front of the film (the position is given in millimeters and the angle is given in degrees).  How far does the lens have to move in order to change the focus between the two objects?    Start

Interactive Hint

More Help.
10 mm.
13 mm.
25 mm.

Physlets used by permission of Wolfgang Christian, Davidson College. Physlet Problems ©Prentice Hall, Inc. Physlet problems on this web site were written by Wolfgang Christian, Mario Belloni, and Aaron Titus.


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