Question

Explain the laws of the concave and convex mirror.

Answer 1

Light is known to behave in a very predictable manner. If a ray of light could be observed approaching and reflecting off of a flat mirror, then the behaviour of the light as it reflects would follow a predictable law known as the law of reflection. The diagram below illustrates the law of reflection.



In the diagram, the ray of light approaching the mirror is known as the incident ray (labelled I in the diagram). The ray of light that leaves the mirror is known as the reflected ray (labelled R in the diagram). At the point of incidence where the ray strikes the mirror, a line can be drawn a perpendicular to the surface of the mirror. This line is known as a normal line (labelled N in the diagram). The normal line divides the angle between the incident ray and the reflected ray into two equal angles. The angle between the incident ray and the normal is known as the angle of incidence. The angle between the reflected ray and the normal is known as the angle of reflection. (These two angles are labelled with the Greek letter "theta" accompanied by a subscript; read as "theta-i" for angle of incidence and "theta-r" for angle of reflection.) The law of reflection states that when a ray of light reflects off a surface, the angle of incidence is equal to the angle of reflection.
Light always reflects according to the law of reflection, regardless of whether the reflection occurs off a flat surface or a curved surface. Using reflection laws allows one to determine the image location for an object. The image location is the location where all reflected light appears to diverge from.
he simpler method relies on two rules of reflection for concave mirrors. They are:
Any incident ray travelling parallel to the principal axis on the way to the mirror will pass through the focal point upon reflection.
Any incident ray passing through the focal point on the way to the mirror will travel parallel to the principal axis upon reflection.