Question

Two thin lenses of powers 2D and 3D are placed in contact. An object is placed at a distance of 30 cm from the
combination. The distance in cm of the image from the combination is​

Answer 1

Explanation:

Power, P=P

1

+P

2

P=(2+3)D

=5D

f=

P

100

=20cm

By lens formula,

v

1

−

u

1

=

f

1

v

1

−

−30

1

=

20

1

v

1

=

60

1

v=60 cm