Question

Write the Lens maker's formula and explain the terms in it.

Answer 1

Lens maker's formula:
$\frac{1}{f}=\frac{n_{lens}-n_0}{n_0}(\frac{1}{R_1}-\frac{1}{R_2})$

where, $f$ is focal length
$n_{lens}$ is refractive index of lens
$n_0$ is refractive index of surrounding (for air, $n_0=1$)
$R_1$ and $R_2$ are radius of curvature of each surfaces.