Two light waves having the same wavelength \(\lambda\) in vacuum are in phase initially. Then the first wave travels a path \( \mathrm{L}_1\) 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 : 📲PW App Link - bit.ly/YTAI_PWAP 🌐PW Website - www.pw.live