Question

In the figure below a ray of light travelling in a medium of refractive index $\mu$ passes through two different rectangular blocks of refractive indices ${\mu }_1$ and ${\mu }_2({\mu }_2>{\mu }_1)$.
The angle of incidence ${\theta }_1$ is increased slightly. Then the angle ${\theta }_2$

• A. Increases
• B. Decreases
• C. Remains the same
• D. Increases or decreases depending on the value of \left ( ${\mu }_1/{\mu }_2$ )

Answer 1

The correct option is B Decreases

Answer is B.

Following are the factors affecting Angle of deviation:

• Angle of incidence
• Angle of prism
• Refractive index
• Wavelength of light used.

From Snell's law, as the angle of incidence is increased, angle of deviation decreases and reaches minimum value. If the angle of incidence is further increased, the angle of deviation is increased.
Hence, as the angle of incidence ${\theta }_1$ is increased slightly, The angle ${\theta }_2$ decreases.