Stand two plane mirrors on their edges and parallel to one another. Place a coin between them near one end. How many images do you see? Draw a ray diagram to explain the formation of the images.

To determine the number of images formed by two parallel plane mirrors, we can use the concept of multiple reflections. By drawing a ray diagram, we can visualize the paths of light rays as they reflect off the mirrors and determine the number of images formed.

Step 1: Draw two parallel lines representing the plane mirrors.

Step 2: Place a coin between the mirrors near one end. Let's assume we place the coin at the left end.

Step 3: Draw a line from the top of the coin (point A) to the top mirror. This ray will reflect off the mirror according to the law of reflection, making an angle equal to the incident angle. Label the reflected ray as A1.

Step 4: Draw a line from the top mirror (A1) to the bottom mirror. This ray will reflect off the bottom mirror, following the same reflection rule, and continue as A2.

Step 5: Draw a second line from the top of the coin (point A) to the bottom mirror. This ray will reflect off the bottom mirror, making an angle equal to the incident angle. Label the reflected ray as A3.

Step 6: Repeat steps 3-5 for the bottom of the coin (point B) to obtain B1, B2, and B3.

By extending the reflected rays, we can observe that they intersect with each other. Each point of intersection represents an image of the coin.

Counting the intersections, we find that there are three images formed by the two parallel plane mirrors.