Question

an object of length 5 cm is placed at the distance of 30cm find the centre of convex lens of focal length 20 cm find the position of the image and its size ​

Answer 1

Formula:

v

1

+

u

1

=

f

1

Given,

v

1

+

(−20)

1

=

15

1

v

1

=

60

7

⇒v=

7

60

v=8.57≈8.6cm

The image is formed behind the mirror at a distance of 8.6 cm

m=

h

1

h

2

=−

u

v

→

5

h

2

=−

20

8.57

∴h

2

=2.175 cm

Thus the image is 2.175 cm high, virtual and erect.

Hence, this is the answer.