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Homework Statement
A thick lens has an index of refraction of 1.560, thickness of 3.0cm, and radii of curvature of R1= -4.50cm, R2= -3.60cm.
Calculate the positions of the focal points (relative to the vertices).
Homework Equations
[itex]\frac{n}{s}+\frac{n'}{s'}=\frac{n'-n}{R}[/itex]
[itex]ffl = \frac{f1(t + f2)}{t-(f1 + f2)}[/itex]
The Attempt at a Solution
I assume I need to first focal length for each lens to plug into the front focal length and back focal length formulas, meaning s' = ∞ so for L1:
f1 = [itex]\frac{R}{n'-n}=\frac{-4.50cm}{1.560-1.000}[/itex] = -8.04cm
Do I have the right idea? If so, will I need to swap the indexes of refraction when doing the opposite side of the lens, so that light is coming from the left side?