Question

17.Find the thickness of a plate which will produce a change in optical path equal to half the wavelength (Lamda) of the light passing through it normally.The refractive index of the plate is (U)-------------

Answer 1

$$\begin{gathered} \mathrm{Optical}\mathrm{path}\mathrm{difference}\mathrm{is}, \\ \left(\mu -1\right)t=\frac{\lambda }{2} \\ where,\mu =\mathrm{refractive}\mathrm{index} \\ t=\mathrm{thickness} \\ \lambda =\mathrm{wavelength} \\ t=\frac{\lambda }{2\left(\mu -1\right)} \end{gathered}$$

Good work Manav.