Question

In the figure below, PQRS denotes the path followed by a ray of light as it travels through three media in succession. The absolute refractive indices of the media are ${\mu }_1,{\mu }_2$ and ${\mu }_3$ respectively. (The line segment RS' in the figure is parallel to PQ). Then

• A. ${\mu }_1>{\mu }_2>{\mu }_3$
• B. ${\mu }_1={\mu }_3<{\mu }_2$
• C. ${\mu }_1<{\mu }_2<{\mu }_3$
• D. ${\mu }_1<{\mu }_3<{\mu }_2$

Answer 1

The correct option is D ${\mu }_1<{\mu }_3<{\mu }_2$

Using snells law ${\mu }_{1}sin{\theta }_1={\mu }_{2}sin{\theta }_2$ as we can see ${\theta }_1>\theta 2\to {\mu }_1<{\mu }_2$

since PQ and RS' are parallel so angle made by RS is less than angle made by PQ, hence ${\mu }_3>{\mu }_2$

so ${\mu }_1<{\mu }_3<{\mu }_2$