AP Physics 2 Lab

Plane

Objective

Draw a diagram to locate an image for a plane .

Materials

List the materials you will use in the lab. You may want to draw a sketch showing the apparatus.

Data

Describe (in complete sentences) 1) the data you will collect (what measurements will you make?) 2) how you will collect the data? (what are the tools you will use?) and 3) how you will use the data. Show any equations you will use to make calculations. Record the data in your data table. It is not necessary to write an entire procedure.

Law of

P’

O R Q M N

• A P B 1. Draw line MN across the middle of a sheet of unlined paper. Place the mirror on the line so the edge of the reflecting surface coincides with MN.

2. Place a pin about 3 or 4 cm in front of the mirror at point P as indicated in the figure above. Place the ruler on the paper at point A, where it is far enough from P so that angle AOP will be at least 60°.

3. Sight along the ruler at the image of the pin as you see it in the mirror. Draw a line along the ruler from A toward the image P’. Repeat for a second sightline at point B.

4. Remove the mirror and extend the sightlines with dashed lines to P’. Draw normal lines to the surface at O and Q. Draw the incident rays PO and PQ on your paper.

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5. Measure the distances PR and P’R and record each of these values in Data Table 1. Measure both of the incident angles and both of the reflected angles. Record each of these values in Data Table 1.

Formation of Images

M N

A

B

C

1. Repeat Procedure 1 from the Law of Reflection above on a second sheet of paper.

2. At least 4 cm in front of the mirror draw a scalene triangle with sides between 4-7 cm. Place a pin at vertex A. Record the lengths of each of the sides of the triangle in Data Table 2.

3. Locate and draw two sightlines for the image of the pin. Label both of these sightlines A. Repeat by drawing sightlines when the pin is located at B and C.

4. Remove the mirror and extend the sightlines behind the mirror (using dashed lines) for each location of the pin. Label the intersections for each pair of sightlines as A’, B’ and C’. Connect A’, B’ and C’ to form triangle A’B’C’. Measure the lengths of the sides of triangle A’B’C’ and record the lengths in Data Table 2.

5. Draw segments AA’, BB’ and CC’. Measure the distance from A to line MN and A’ to line MN. Record each of these values in Data Table 2. Repeat for B, B’ and C, C’.

Analyze

1. How closely do your results support the Law of Reflection?

2. How closely do your results support the following statements regarding plane mirrors?

a. “An image is located the same distance behind of a plane mirror that the object is located in front of the mirror.”

b. “The size of the image produced by a plane mirror is the same size as the object.”

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3. Does the location of the viewer determine the location of the image behind the mirror? Justify your answer.

4. Explain why the reflection of light rays from the plane mirror is and how this type of reflection produces an image.

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AP Physics 2

Plane Mirrors

Data Table 1

Reflected Incident Reflected Incident Angle PR (cm) P’R (cm) Angle for Angle for Angle for For Sightline A Sightline A Sightline B Sightline B

Data Table 2

Length of Triangle Sides (cm) Distance to MN (cm)

AB BC CA A B C

A’B’ B’C’ C’A’ A’ B’ C’

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