1. PHYSICS
REFLECTION OF LIGHT AT
PLANE OR CURVED SURFACES
Short revision series

2.  2 types of reflection: Regular and Scattered
(diffused)
incident reflected
REGULAR
incident reflected
DIFFUSED

3. Laws of reflection
1. The incident ray, the reflected ray and the
normal at the point of incidence all lie in
the sme plane.
2. The angle of incidence is equal to the angle
of reflection.
 i = r
i r

4. Images in plane mirror
 Virtual image: one that cannot be formed on
the screen.
 A real image can be formed on the screen
An image in a plane mirror displays the
following characteristics
1. Same size as the object
2. Same distance behind the mirror as the
object is to the front
3. Laterally inverted
4. Virtual and upright

5. Inclined mirrors
 When a mirror is rotated through an angle θ
the angle of rotation of reflected ray =
(2i+2θ)-2i =2θ
 The reflected ray always turns through twice
the angle of rotation

6. Reflection by curved mirrors: convex
mirrors

7. Reflection by curved mirrors:
concave mirrors

8. Mirror formulae
 CONCAVE MIRRORS
 1/F = 1/u + 1/v
 In concave mirrors the principal focus is real
so focal lenght f is positive. So image formed is
real;
 1/F = 1/u – 1/v * when v is negative
 Magnification = v/u
 u = distance of object
 v = distance of image

9. Mirror formulae
 CONVEX MIRRORS
 1/(-F) = 1/u + 1/(-v)
= 1/u – 1/v = - 1/F
 In convex mirrors principal focus is virtual ,
focal lenght is negative but object distance u is
positive.