Question

a concave lens of power 10d is placed in contact with convex lens of 2d what will be the nature of combined lens​

Answer 1

Answer:

Given,

P

1

=

f

1

1

=+10D

P

2

=

f

2

1

=−5D

M=2

The focal length of the combination,

f

1

=

f

2

1

+

f

2

1

f

1

=10−5=+5D

f=

5

100

=20cm

For virtual image, M=

u

v

v=2u

From lens formula

f

1

=

v

1

−

u

1

20

1

=

2u

1

−

u

1

20

1

=−

2u

1

u=−10cm