Question

A plane mirror reflects a beam of light to form a real image. The incident beam is:
A. Parallel.
B. Convergent.
C. Divergent.
D. Any one of the above.

Answer 1

Hint:- A mirror always produces a virtual image of a real object whether it is a convex or a concave mirror. The plane mirror has a focal length of infinity so if a parallel beam of ray is projected on the plane mirror then there will be no deviation and the parallel beam will just get reflected.

Complete step-by-step solution:

The focal length of the plane mirror is infinite if a parallel beam of ray falls on the surface of the plane mirror then the rays get deflected and they will not have any image as all the rays due to beam were parallel to each other therefore they all just get reflected. If an object is kept in front of the plane mirror then the beam of rays that will strike the surface of the plane mirror will be divergent and the image formed will be a virtual image.

The beam of rays are diverging here and therefore the image formed is a virtual image which is formed on the opposite side of the mirror. We have seen the image formed by the plane mirror. If a divergent ray falls on the mirror now let us see if the beam of rays are convergent then what nature of image will be formed by the plane mirror.
If the convergent rays fall on a plane mirror then the rays will converge at a point and form a real image but the object will seem on the other side of the plane mirror and therefore the object is known as virtual object.

The real image is formed when the beam of rays are convergent. The correct answer for this problem is option B.

Note:- The image formed by the plane mirror seems like it is coming from the other side of the mirror which means that the image formed by the plane mirror is always a virtual image but in order to get a real image the rays of the beam should be converging in nature and for this case the object will be virtual object.