Cross-section view of a prism is the equilateral triangle ABC shown in the figure. The minimum deviation is observed using this prism when the angle…

Cross-section view of a prism is the equilateral triangle ABC shown in the figure. The minimum deviation is observed using this prism when the angle of incidence is equal to the prism angle. The time taken by light to travel from P (midpoint of BC) to A is \_\_\_\_ $\displaystyle \times 10^{-10} \mathrm{~s}$. (Given, speed of light in vacuum $\displaystyle =3 \times 10^8 \mathrm{~m} / \mathrm{s}$ and $\displaystyle \cos 30^{\circ}=\frac{\sqrt{3}}{2}$ )