Question

Where is the image in a plane mirror formed?

Your friend Noelle suggests the following hypothesis: "The image of an object formed by a plane mirror is formed on the surface of the mirror." Design an experiment to test Noelle's hypothesis.

Available equipment: Plane mirror, object, masking tape, paper, meter stick.

Design and describe the experiment that you plan to perform. Remember that your prediction of the outcome if the expirement must allow from the hypothesis you are testing. Then perform the experiment and record the outcome. Explain the outcome using a ray diagram. Discuss whether the outcome agrees or disagrees with the prediction. If it disagrees, how would you convince Noelle that her idea has been disproven?

Answer 1

One of the important principle for viewing an image in plane mirror is,

First we must sight at the image; when you sight at the image, light will come to your eye along that line of sight.

The image location is thus located at that position where observers are sighting when viewing the image of an object. It is the location behind the mirror where all the light appears to diverge from. In the diagram below, three individuals are sighting at the image of an object along three different lines of sight. Each person sees the image due to the reflection of light off the mirror in accordance with the law of reflection. When each line of sight is extended backwards, each line will intersect at the same point. This point is the image point of the object.

A ray diagram for a plane mirror is shown above. The incident light rays from the object create an apparent mirror image for the observer.

How to see an object in a plane mirror. First we have to see the rays coming from the object to see it. If the light first hits the mirror and then reflects with the same angle, the extensions of the reflected rays are focused at one point behind the mirror. We see the coming rays as if they are coming from the behind of the mirror. At point A’ image of the point is formed and we call this image virtual image which means not real.

The distance of the image to the mirror is equal to the distance of the object to the mirror. If we want to draw the image of an object in plane mirrors we follow the given steps below. First look at picture and then follow the steps one by one.

In plane mirrors, we use the laws of reflection while drawing the image of the objects. As you see from the picture we send rays from the top and bottom of the object to the mirror and reflect them with the same angle it hits the mirror. The extensions of the reflected rays give us the image of our object. The orientation and height of the image is same as the object. In plane mirrors always virtual image is formed.