Thin lens formula
$$\frac{1}{F} = (\frac{n1}{n2}-1)\cdot (\frac{1}{R1}+\frac{1}{R2})$$
F - focal distance
n1 - refraction index of the lens
n2 - refraction index of the environment
R1, R2 - radii of curvature of the two surfaces
n1 - refraction index of the lens
n2 - refraction index of the environment
R1, R2 - radii of curvature of the two surfaces
Find
It is known that:
= 