The radius of curvature of the convex face of a planoconvex lens is 15 cm and the refractive index of the material is 1.4. Then the power of the lens in dioptre is

Options

A. A)`1.6`
B. B)`1.66`
C. C)`2.6`
D. D)`2.66`

Answer

D

Explanation

`(1)/(f)=(mu-1)((1)/(R_(1))-(1)/(R_(2)))` For planocinvex lens `R_(1)=oo,R_(2)=-R=-1.5cm,mu=1.4`
`therefore(1)/(f)=(1.4-1)(0+(1)/(15))or(1)/(f)=0.4xx(1)/(15)`
Therefore , power of the lens in diopter `P=(100)/(f)=(40)/(15)=2.66D`