Question

2 convex lens each of focal length 50 cm and a concave lens of focal length 20 cm are placed in close contact. Find the power of combination​

Answer 1

P

convex

1

=

50

100

=+2D

P

concave

1

=

−50

100

=−2D

P

concave

2

=

−20

100

=−5D

P

eq

=−2−5+2

=−5D