MCQ
Two light waves having the same wavelength $\lambda$ in vacuum are in phase initially. Then the first wave travels a path $L _{1}$ through a medium of refractive index $n_{1}$ while the second wave travels a path of length $L_{2}$ through a medium of refractive index $n _{2}$. After this the phase difference between the two waves is:
- ✓$\frac{2 \pi}{\lambda}\left( n _{1} L _{1}- n _{2} L _{2}\right)$
- B$\frac{2 \pi}{\lambda}\left(\frac{ L _{2}}{ n _{1}}-\frac{ L _{1}}{ n _{2}}\right)$
- C$\frac{2 \pi}{\lambda}\left(\frac{ L _{1}}{ n _{1}}-\frac{ L _{2}}{ n _{2}}\right)$
- D$\frac{2 \pi}{\lambda}\left( n _{2} L _{1}- n _{1} L _{2}\right)$
