Physics

Physics · optics

Problem

Example 16: White light is incident on a soap film at an angle

\sin ^{-1} \frac{4}{5}

and the reflected light is observed with a spectroscope. It is found that two consecutive dark bands correspond to wavelengths

6.1 \times 10^{-5}

and

6.0 \times 10^{-5} \mathrm{~cm}

. If the refractive index of the film be

4 / 3

, calculate the thickness. [UPTU, B.Tech. II Sem. 2007]