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A thin converging lens has a power of 4.0 diopters determ...

A thin converging lens has a power of 4.0 diopters determined its focal length.

A.

2.50m

B.

0.03m

C.

5.00m

D.

0.25m

Correct answer is D

the power of a lens is defined as the reciprocal of the focal length ,expressed in metre.Mathematically, the power of a lens in dioptres is given by:(1)/f(in cm).
thus for lens of power of 4.0 dioptres we have that: (1)/(f) = +4.0
f= (1)/(4.0) 
= 0.25cm