ISC Class 12 Physics demands rigorous optical ray diagrams and mathematical derivations from first physical principles.
Lens Maker's Formula Derivation
$\frac{1}{f} = (\mu - 1) \left(\frac{1}{R_1} - \frac{1}{R_2}\right)$. The derivation requires evaluating refraction at two consecutive spherical surfaces. Clearly label the virtual object formed by the first refracting interface.