Question

what is a power of a lens and define its unit? Three friends A,B,C has lenses of focal length 50,100,-100. Identify the nature of each of lens and find power of each of lens

Answer 1

A = f =1/50 =0.5 d(dioptre)             converging lens
B=f=1/100=0.01 d                        converging lens
c=f=1/-100= -0.01 d                 diverging lens