The drawing shows a ray of light traveling from point $A$ to point $B,$ a distance of $4.60 \mathrm{m}$ in a material that has an index of refraction $n_{1}$ At point $B$, the light encounters a different substance whose index of refraction is $n_{2}=1.63 .$ The light strikes the interface at the critical angle of $\theta_{\mathrm{c}}=$ $48.1^{\circ} .$ How much time does it take for the light to travel from $A$ to $B ?$