find the focal length and the nature of lens which should be placed in the contact with a lens of - Physics - Force and Pressure

Question

find the focal length and the nature of lens which should be
placed in the contact with a lens of focal length 10cm so that the
power of the combination becomes 5d

Roopa jayasimha · Accepted Answer

1/f = 5
f = 1/5
f = 0 2 m
Hence it has a positive sign and is a convex lens

find the focal length and the nature of lens which should be placed in the contact with a lens of focal length 10cm so that the power of the combination becomes 5d.