Time taken by light to travel in two different materials A and B of refractive indices μ_A and μ_B of same thickness is t_1 and t_2 respectively. If…

Time taken by light to travel in two different materials A and B of refractive indices $\displaystyle \mu_A$ and $\displaystyle \mu_{\mathrm{B}}$ of same thickness is $\displaystyle \mathrm{t}_1$ and $\displaystyle \mathrm{t}_2$ respectively. If $\displaystyle \mathrm{t}_2-\mathrm{t}_1=5 \times 10^{-10} \mathrm{~s}$ and the ratio of $\displaystyle \mu_{\mathrm{A}}$ to $\displaystyle \mu_{\mathrm{B}}$ is $\displaystyle 1: 2$. Then, the thickness of material, in meter is : (Given $\displaystyle v_{\mathrm{A}}$ and $\displaystyle v_{\mathrm{B}}$ are velocities of light in A and B materials respectively.)