Lensmakers equation:

1/f = (n₁/n_m-1) * (1/r₁-1/r₂)

Where,
n₁ -Refractive Index of Lens Material
n_m -Refractive Index of Ambient Medium
r₁ -Radius of Curvature of the First Surface
r₂ - Radius of Curvature of the Second Surface

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