- Laws of reflectionWhen light is reflected from a smooth surface , the angle of incidence and angle of reflection are equal. The incident ray the reflected ray and the normal to the surface are in the same plane.
- When light falls on a smooth surface, it undergoes a regular reflection.
- When light falls on a. rough surface it undergoes an irregular reflection.
- After regular reflection the light rays travel parallel.
- The field of view of a mirror is the maximum range of the vision through the mirror.
- New Cartesian Sign Convention
In all experiments related to lens and mirrors the distances are measured in the same way as in graphs.
Distance are measured considering the pole of the mirror as the origin.
Those measured to the right from O are positive and those in the opposite direction are negative.
Distance measured upwards from X axis are positive and those downwards are negative.
The incident ray is to be considered as travelling from left to right. - Magnification
The ratio of the height of the image to the height of the object is magnification.
Magnification = 1, Size of the image = Size of the object
Magnification > 1, Size of the image > Size of the object
Magnification < 1. Size of the image < Size of the object
Magnification positive - Image erect and virtual
Magnification negative - Image inverted and real
Formulae to remember
Number of images(n)
$$n = \frac{360}{\Theta}-1$$
$$\Theta = Angle-between-mirrors$$
Focal length (f) =
$$\frac{uv}{u + v} $$
$$\frac{1}{f} = \frac{1}{u} + \frac{1}{v} $$
f = Focal length, U = Distance to object from the mirror, V = Distance to the image from the mirror.
Magnification
$$ m = \frac{hi}{ho}$$
$$ m = \frac{-v}{u}$$
hi : Hight of image
ho : Hight of object