Question

The velocity of light is maximum in a medium of (A) diamond (B) water (C) glass (D) vacuum

Short answer

The maximum velocity of light occurs in a medium of a vacuum (option D), as it has the lowest refractive index (1.0), allowing light to travel at its fastest speed of approximately \(3.00 \times 10^{8}\) meters per second.

Step-by-step solution

Understanding the velocity of light in different mediums

The velocity (speed) of light depends on the medium through which it is passing. In general, light travels at its maximum speed in a vacuum. When light passes through a medium, its speed is reduced in relation to the refractive index of that medium. The refractive index is a measure of how much the medium can bend or slow down the light. The higher the refractive index, the more the light is bent, and hence the slower the speed of light in that medium.

Comparing the refractive indices of the given mediums

We know that the velocity of light is inversely proportional to the refractive index of the medium. Thus, to find the medium with the maximum velocity of light, we need to compare the refractive indices of the given mediums: - Diamond: Refractive index is around 2.42 - Water: Refractive index is around 1.33 - Glass: Refractive index is around 1.5 (may vary depending on glass composition) - Vacuum: Refractive index is 1.0 (by definition)

Determining the medium with maximum velocity of light

Since the velocity of light in a medium is inversely proportional to its refractive index, the medium with the lowest refractive index will have the highest velocity of light. Clearly, the vacuum has the lowest refractive index (1.0), which corresponds to the highest speed of light (approximately \(3.00 \times 10^{8}\) meters per second).

Answer

The maximum velocity of light occurs in a medium of a vacuum (option D).