Question

An eye specialist prescribes spectacles having a combination of a convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. The power of this lens combination will be

Answer 1

Answer:

100/40 + 100/25

-5/2+4

-5+8/2

= 3/2

=1.5d

1.5 d will be the total power