Question

Which of the following statements are true for an image formed by a plane mirror?

 

	The image always appears to be located the same distance behind the mirror as the object is located in front of the mirror.
	The image formed by a plane mirror is always a real image.
	The image is always larger than the object.
	The image formed by a plane mirror is always an upright image.
	The image formed by a plane mirror is always an inverted image.
	The image formed by a plane mirror is always a virtual image.

Answer 1

The concepts needed to explain the question are a ray diagram to trace the image formed by a plane mirror and the nature of the image formed by a plane mirror.

First draw the ray diagram to trace the image formed by a plane mirror, explain the virtual images and real images, and explain the options.

In the case of ray diagrams, the images can be traced in two ways. One is by meeting the real reflected or refracted rays. The other way is by extending the reflected or refracted rays backward. The second case is used when the real reflected or refracted ray is not diverging.

In a ray diagram, the image is real when the image is traced by the actual meeting of the rays after reflection or refraction.

In a ray diagram, the image is virtual when the image is traced by the rays which are appeared to meet after reflection or refraction.

The ray diagram to trace the image formed by a plane mirror is as follows:

In the figure, the line MN represents the plane mirror, the solid lines represent the real light rays, and the dotted lines represent the extended or virtual light rays.

In the ray diagram, the image is traced by extending the reflected ray. Hence, the image should be virtual as per the definition of the virtual image.

So, the statement ‘the image formed by a plane mirror is always a real image’ is incorrect.

From the ray diagram, it is clear that the size of the image is as same the size of the object. Hence, the statement ‘The image is always larger than the object’ is incorrect.

From the ray diagram, it is clear that the image is upright with respect to the object. Hence, the statement ‘The image formed by a plane mirror is always an inverted image’ is incorrect.

The image always forms at the same distance of object as the virtual rays appear to be coming from the same distance of the object.

From the above explanation, the following statements are correct:

The image always appears to be located the same distance behind the mirror as the object is located in front of the mirror.  

The image formed by a plane mirror is always an upright image.

The image formed by a plane mirror is always a virtual image.