Refractive index of a medium nm is related to the speed of light in that medium v by the relation:
\(n_m = \frac{\text{Speed of light in air }}{\text{Speed of light in the medium }}= \frac{c}{ v}\)
Where, c is the speed of light in vacuum/air.
The refractive index of diamond is 2.42. This suggests that the speed of light in diamond will reduce by a factor 2.42 compared to its speed in air.
In the adjoining figure, \( AP = 1 \, \text{cm}, \ BP = 2 \, \text{cm}, \ AQ = 1.5 \, \text{cm}, \ AC = 4.5 \, \text{cm} \) Prove that \( \triangle APQ \sim \triangle ABC \).
Hence, find the length of \( PQ \), if \( BC = 3.6 \, \text{cm} \).