Reflection of light

Reflection of light

Light moving in one medium when falls at the surface of another medium, part of light returns back to the same medium. This phenomenon of returning back of light in the first medium at the interface of two media is known as reflection of light.

Laws of reflection

1. The incident ray, reflected ray and normal to the reflecting surface at the incident point all lie in the same plane.
2. The angle of reflection is equal to the angle of incidence.

Reflection from plane mirror

1. The image is virtual, laterally inverted.
2. The size of image is equal to that of object.
3. The distance of image from the mirror is equal to distance of object from the mirror.
4. If an object moves towards (or away from) a plane mirror with speed v, the image moves towards (or away) with a speed 2v relative to the object.
5. If a plane mirror is rotated by an angle 0, keeping the incident ray fixed, the reflected ray is rotated by an angle 20.
6. To see his full image in a plane mirror, a person requires a mirror of at least half of his height.

Uses of Concave mirror :

1. As a shaving glass.
2. As a reflector for the head lights of a vehicle, search light.
3. In opthalmoscope to examine eye, ear, nose by doctors.
4. In solar cookers.

Uses of Convex mirror :

1. As a rear view mirror in vehicle because it provides the maximum rear field of view and image formed is always erect.
2. In sodium reflector lamp.