Optics — Easy Practice (Set 2)

Quick Recap — Lenses, Prism & Wave Optics

• Thin lens: $\dfrac{1}{v} - \dfrac{1}{u} = \dfrac{1}{f}$; lens maker's formula $\dfrac{1}{f} = (n-1)\left(\dfrac{1}{R_1} - \dfrac{1}{R_2}\right)$; power $P = \dfrac{1}{f}$ (dioptres); lenses in contact add their powers.
• Prism: $n = \dfrac{\sin\frac{A+\delta_m}{2}}{\sin\frac{A}{2}}$; for a small angle $\delta = (n-1)A$.
• Huygens' principle: every point on a wavefront acts as a source of secondary wavelets.
• Young's double slit: fringe width $\beta = \dfrac{\lambda D}{d}$; bright fringes at path difference $n\lambda$, dark at $\left(n-\tfrac12\right)\lambda$.
• Polarization (light is transverse): Malus $I = I_0\cos^2\theta$; Brewster $\tan\theta_B = n$.