Question

What type of mirror is used by motorists to see the road behind them?
A) Convex
B) Concave
C) Plane
D) Concave Convex

Answer 1

A mirror is the most widely used reflecting surface, the type of image obtained from a mirror can be explained by the law of reflection which states that, when light is reflected from a surface the angle of incidence is always equal to the angle of reflection, where both angles are measured from the path of the light to the normal to the surface at the point at which light strikes the surface.

Complete answer:
Suppose you are riding a bike on a busy highway and there are many vehicles ahead of you as well as behind you. Now, you want to make a left turn but you can not afford (because there are vehicles in front of you as well) to turn back and see if there’s any vehicle approaching you from behind on the left side. So to help you see the road behind you the motorcycle manufacturer provides you the rear view mirrors on your bike.

The rear view mirror must be able to cover a wider field of view (of course for this the images must be diminished) so that you will be able to see the most of the traffic behind you. So neither a plane nor a concave mirror can provide us a diminished image with a wider field of view, but only a convex mirror is suitable for this purpose.

Hence, option (A) is the correct answer.

Note:
There are three types of mirrors that are most commonly used. They are:
Plane Mirror: The images that are formed on a plane mirror are of their normal proportions but are reversed from left to right.
Concave Mirror: This is a spherical mirror which is curved inward and the nature of image depends on the placement of the object.
Convex Mirror: This is a spherical mirror which is curved outward and the images obtained are virtual, diminished and erect.