Definitions [5]
Define the terms: a ray of light and a beam of light.
The light traveling in any one direction in a straight line is called a ray of light.
A group of light rays given out from a source is called a beam of light
Define Regular reflection.
The phenomenon due to which a parallel beam of light traveling through a certain medium, on striking some polished surface, bounces off from it, as a parallel beam, in some other direction, is called regular reflection.
Define the term Principle axis.
The principal axis is the straight line passing through the pole and the centre of curvature.
Define reflection.
The bouncing of light by any smooth or polished surface is called.
The phenomenon of bouncing back of light rays in the same medium on striking a surface is called reflection of light.
Formulae [1]
n = \[\frac {360°}{θ}\]
- If n is even → N = n − 1
- If n is odd → N = n (object not on bisector); N = n − 1 (object on bisector)
- If n is a fraction → N = integral part of n
Theorems and Laws [1]
- The angle of incidence ∠i = angle of reflection ∠r.
- The incident ray, reflected ray, and normal lie in one plane; both rays are on either side of the normal.
Key Points
- Reflection occurs when light bounces off a smooth surface like a mirror, following fixed laws.
- Plane mirrors always form virtual, erect, and same-sized images that are laterally inverted.
- Curved surfaces (like a spoon) act as spherical mirrors, changing the image size and orientation depending on the object's position.
