2. Objectives:
• To show how rays travel in order to
form images in a concave mirrors.
• To show and state the nature of
images formed.
3. The paths of three
rays are known.
a. Rays traveling parallel to the principal
axis
b. Rays passing through the principal
focus
c. Rays passing through the centre of
curvature
4. C F P
(a) Rays parallel to the principal
axis are reflected and they pass
through the principal focus
5. (b) Rays passing through the
principal focus (F) will move
parallel to the principal axis
after reflection
C F P
6. (c) Ray passing through the centre
of curvature (C) are reflected
back along their own paths
because they are normal to the
mirror
C F P
7. FC P
I am parallel to the principal
axis. Always draw me first
I am the
Object
I am reflected parallel to
the principal axis
Now let us draw a ray diagram for
an object beyond C
8. FC P
I am parallel to the principal
axis. Always draw me first
I am the
Object
I am reflected parallel to
the principal axis
Now let us draw a ray diagram for an object at
C
I am the image.
What is my
nature?
9. FC P
I am parallel to
the principal axis.
I am the
Object
I am reflected parallel to the principal axis
Now the object is between C and F
I am the image
now. What is
my nature?
10. FC P
I am the
Object
Now let us draw a ray diagram for an object at
F
We will meet at
infinity to form a
real, inverted
magnified image.
11. FC P
I am the
Object
I am reflected parallel to
the principal axis
Now let us draw a ray diagram for an object
between F and P
I am the image.
What is my
nature now?
