Question

A lens is formed from a plastic material that has an index of refraction of 1.59 . If the radius of curvature of one surface is 1.15 m and the radius of curvature of the other surface is 1.80 m , use the lensmaker's equation to calculate the magnitude of the focal length | f | and the power | P | of the lens.

Answer 1

a) 5.39 m

b) 0.18 m^-1

Step-by-step explanation:

The focal length of this kind of optical system is given by:

`(1)/(f)\approx(n-1)[(1)/(R_1)-(1)/(R_2)]`

you replace the values of the parameters in order to find the focal length:

`(1)/(f)=(1.59-1)[(1)/(1.15m)-(1)/(1.80m)]=0.18m^-1\\\\f=(1)/(0.18)m=5.39m`

hence, the magnitude of the focal length is 5.39m

The power of the lens is:

`P=(1)/(f)=0.18\ m^(-1)`

the power of the lens is 0.18 m^-1