3. CONTENTS
CONCAVE MIRROR
PARTS OF CONCAVE MIRROR
RULES FOR OBTAINING IMAGE
FORMED BY CONCAVE MIRROR
DIFFERENT TYPES OF IMAGES FORMED
BY A CONCAVE MIRROR
USES OF CONCAVE MIRRORS
4. CONCAVE MIRROR
A concave mirror is that spherical mirror in
which the reflection of light takes place at
the concave surface
5. PARTS OF CONCAVE MIRROR
Centre of curvature (C)
Radius of curvature (R)
Pole (P)
Principal Axis
Principal Focus (F)
P
<_____R__>_
6. RULES FOR OBTAINING IMAGES FORMED
BY A CONCAVE MIRROR
RULE -1
A ray of light which
is parallel to the
principal axis of a
concave mirror ,
passes trough its
focus after reflection
from the mirror
7. Rule 2
A ray of light passing
trough the centre of
curvature of a
concave mirror is
reflected back along
the same path
8. Rule 3
A ray of light passing
trough the focus of a
concave mirror
becomes parallel to
the principal axis after
reflection
9. FORMATION OF DIFFERENT TYPES OF
IMAGES BY A CONCAVE MIRROR
Positions of the object :
between the pole (P) and focus (F)
At the focus (F)
between focus (F) and centre of curvature (C)
At the centre of curvature (C)
beyond the centre of curvature (C)
At infinity
10. WHEN THE OBJECT IS PLACE BETWEEN
POLEAND FOCUS OF THE MIRROR
(OBJECT BETWEEN P AND F)
NATURE OF IMAGE
behind the mirror
Virtual and errect
larger than the
object
11. WHEN THE OBJECT IS PLACED AT FOCUS OF
A CONCAVE MIRROR (OBJECT AT F)
NATURE OF IMAGE
at infinity
real and inverted
highly magnified
or enlarged
12. WHEN THE OBJECT IS PLACED BETWEEN
FOCUS AND CENTRE OF CURVATURE
(OBJECT BETWEEN F AND C)
NATURE OF IMAGE
beyond the centre of
curvature
real and inverted
larger than the object
13. WHEN THE OBJECT IS PLACED AT THE
CENTRE OF CURVATURE OF ACONCAVE
MIRROR (OBJECT AT C)
NATURE OF IMAGE
at the centre of
curvature
real and inverted
same size as the
object
14. WHEN THE OBJECT IS BEYOND THE CENTRE
OF CURVATURE OF A CONCAVE MIRROR
(OBJECT BEYOND C)
NATURE OF IMAGE
between the focus
and centre of
curvature
real and inverted
smaller than the
object
15. WHEN THE OBJECT IS AT INFINITY
NATURE OF IMAGE
at the focus
real and inverted
much smaller than
the object (or highly
diminished)
16. USES OF CONCAVE MIRRORS
Concave mirrors are used -
As reflectors in car head-lights
,search lights ,hand
torches ,and table lamps.
By doctors to concentrate
light on body parts like
ears and eyes.
In the field of solar
energy to focus sun-rays
on the objects to be
heated.
As shaving mirrors.
17. SUMMARISATION
So far we had discussed-
Concave mirrors
Parts of concave mirrors
Different types of images formed by a
concave mirror
Uses of concave mirror
18. EVALUATE YOURSELF
Q1)A ray of light which is parallel to the principal
axis of a concave mirror ,after reflection
a) passes through its focus
b) is reflected back along the same path
c) becomes parallel to the principal axis
d) passes through the centre of curvature
19. Q2) When the object is placed at centre of
curvature ,then image is formed
a) behind the mirror
b) between focus and centre of curvature
c) beyond centre of curvature
d) at centre of curvature
20. Q3) When the object is placed at the focus of
a concave mirror, then image is formed
a) behind the mirror
b) at infinity
c) at the focus
d) beyond centre of curvature
