Question

When light ray refracts on entering from one medium to another medium of different refractive indices, it follows:

• A. Minimum distance
• B. Minimum time
• C. Maximum time
• D. Maximum distance

Hint:

Fermat's Principle is a powerful concept in optics. Think of it like a lifeguard saving a swimmer: the lifeguard doesn't run in a straight line to the swimmer, but runs a longer distance on the sand (where they are fast) and a shorter distance in the water (where they are slow) to minimize the total time.

Answer 1

The Correct Option is B

The guiding principle for the path of light, which covers reflection and refraction, is Fermat's Principle of Least Time. This principle states that the path a light ray takes between two points is the path that can be traveled in the least amount of time. When light travels in a uniform medium, its speed is constant, and the path of minimum time is a straight line (the minimum distance). However, when light refracts, its speed changes as it enters the new medium. To minimize the total travel time, the light bends, following a path that is not the shortest distance but is the quickest. Snell's law can be derived from this principle.