Question

When light enters normally into turpentine oil ($n=1.47$) from water ($n=1.33$), it experiences:

• A. Increase in its speed
• B. Change in its direction
• C. Decrease in its speed
• D. Reflection

Answer 1

The correct option is C Decrease in its speed

Turpentine oil has higher refractive index than water. Hence, it is optically denser than water and the speed of light decreases when it enters turpentine oil. Since, the light enters the oil normally (perpendicularly), it does not experience any change in its direction or refraction.