we put 2 mirrors perpendicular to each other and then an object in front. the result is 3 images of that object. how does the middle image occur?
The middle image appears directly behind the intersection of the two mirrors, and is a double-reflection off of two mirrors. There is no right-left reversal in that image, becasue of the even number of reflections.
To understand how the middle image occurs when two mirrors are placed perpendicular to each other, let's break it down step by step:
1. Start with two mirrors, labeled Mirror A and Mirror B, placed perpendicular to each other. The intersection point where the mirrors meet is called the vertex (V).
2. Place an object in front of the mirrors, perpendicular to the surface of Mirror A. Let's call this object O.
3. When light from the object O hits Mirror A, it reflects off the mirror at an angle of incidence (angle of incoming light) equal to the angle of reflection (angle of outgoing light), according to the law of reflection.
4. The light rays reflected from Mirror A will then hit Mirror B, and the same process of reflection occurs. The angle of incidence will be equal to the angle of reflection.
5. Since Mirror A and Mirror B are perpendicular to each other, the angle of incidence on Mirror B will be perpendicular to the angle of reflection on Mirror A.
6. As a result, the light rays reflected from Mirror B will converge and meet at the vertex V, forming an image of the object O behind the intersection point.
7. This image is known as the middle image. It is seen through both mirrors and is formed by double-reflection off of the two mirrors.
8. Unlike the other two images formed by the mirrors, the middle image does not undergo a right-left reversal. This is because there is an even number of reflections involved (two reflections) between the object O and the observer's eye.
In summary, the middle image occurs when light reflects off Mirror A, then Mirror B, and converges at the vertex V, creating an image behind the mirrors. Unlike the other two images, the middle image is not reversed horizontally due to the even number of reflections.