Page 141 - Science Class 07

v The angle of incidence is equal to the angle plane mirror and eat with your right hand. It
of reflec on. will appear in the mirror that you are ea ng

Incident Normal Reflected with your le hand.
Ray Ray
You might have seen an ambulance. At the
front side of the ambulance, the word
‘AMBULANCE’ is wri en laterally inverted like
this— ‘ ’ so that it may appear correct
in the rear view mirror of the vehicle moving
Plane
(Mirror) i r ahead.

Laws of Reflec on

PLANE MIRROR Lateral Inversion

A plane mirror is a smooth surface that reflects USES OF PLANE MIRRORS
most of the light striking it.
Plane mirrors are used in daily life as under:
Remember that, the mirror absorbs a very
v They are used as looking glasses to see how
small frac on of light because it is very smooth
we look, while shaving and dressing.
for a sharp reflec on. It is coated from one side
v They are used to maintain a the distance of
with a thin layer of silver and aluminum.
the chart used for tes ng eye-sight.
Mirrors are of two kinds in terms of shape:
v They are used for ge ng mul ple images
v Plane mirrors v Spherical mirrors
of the same object by keeping plane
mirrors at proper angles to one another.

KINDS OF REFLECTION

As you know reflec on takes place when light
strikes a smooth surface. Therefore, the surface
plays a vital role in reflec on and on the basis
of the nature of the surface reflec on is also of
two kind—Regular Reflec on and Irregular
Reflec on.
Plane Mirror Spherical Mirror Regular Reflec on

Lateral Inversion When a parallel beam of light strikes a smooth

Lateral inversion is a phenomenon in which le surface and bounces back as a parallel beam of
hand side of an object appears as right hand light, then such kind of reflec on is called
side and vice-versa. regular reflec on. Mirrors, water, oil and highly
polished metals cause regular reflec on.
The images formed by a plane mirror are
always laterally inverted. If you sit before a

Science-7 141