A convex lens with index of refraction n 160 has two spheri

A convex lens with index of refraction n = 1.60 has two spherical surfaces as shown in the diagram. The radius of curvature of the left face is r1 = 1.50 m. The radius of curvature of the right face is r2 = 1.70 m. What is the focal length (in m) of this lens?

Solution

Using lens maker\'s formula :

1/f = (n - 1) ( 1/R1 - 1/R2)

n = 1.60

R1 = 1.50 m

R2 = - 1.70 m

1/f = (1.60 - 1) ( 1/1.50 - 1/(-1.70) )

1/f = 0.753

f = 1.33 m .............Ans