Question

Q11) An object 2 cm high is placed at a distance of 16 cm from a concave mirror which
produces a real image 3 cm high.
(a) Find the position of the image.
(b) What is the focal length of the mirror?
​

Answer 1

Answer:

Here h

1

= 2 cm, u = -16 cm, h

2

= -3 cm (Since image is real and inverted.)

∵m=

h

1

h

2

=−

u

v

∴v=

h

1

−h

2

u=

2

3

×(−16)=−24cm

f

1

=

v

1

+

u

1

=−

24

1

−

16

1

=

48

−2−3

=

48

−5

;f=

5

−48

=−9.6cm