Answer:
The value [tex]f = 21.49 \ cm[/tex]
Explanation:
From the question we are told that
The index of refraction is [tex]n = 1.60[/tex]
The outer radius of curvature is [tex]R = 2.08 \ cm = 0.0208 \ m[/tex]
The inner radius is [tex]r = 2.48 \ cm = 0.0248 \ m[/tex]
Generally from Maker's equation we have that
[tex]\frac{1}{f} = [n - 1 ][\frac{1}{(R)} - \frac{1}{r} ][/tex]
=> [tex]\frac{1}{f} = [1.60 - 1 ][\frac{1}{( 0.0208 )} - \frac{1}{0.0248} ][/tex]
=> [tex]\frac{1}{f} = 4.65[/tex]
=> [tex]f = 0.2149 \ m[/tex]
=> [tex]f = 21.49 \ cm[/tex]