Which one of the following media has maximum speed of light?

Correct option is A

The correct answer is: (a) Air 

The speed of light is maximum in a vacuum, where it is approximately 3×10⁸m/s. In other media, the speed of light decreases due to the refractive index of the material. The refractive index determines how much the light slows down compared to its speed in a vacuum.

Comparison of Media:

The medium with the lowest refractive index (closest to 1) allows light to travel faster.

• Air:

  • Refractive index ~1.0003 (close to 1, so light travels fastest).

• Water:

  • Refractive index ~1.33. Light travels slower in water compared to air.

• Glass:

  • Refractive index ~1.5. Light slows down more in glass than in water.

• Diamond:

  • Refractive index ~2.42. Light has the lowest speed in diamond due to its high refractive index.

Additional Information:

Relationship Between Speed of Light and Refractive Index:

v=cnv = \frac{c}{n}v=c/n

Where:

• $v$: Speed of light in the medium.
• $c$: Speed of light in a vacuum.
• $n$: Refractive index of the medium.

Key Point: Higher the refractive index, slower the speed of light.

Applications of Light Speed in Media:

1. Optics:

   • Helps in understanding refraction and designing lenses for glasses, cameras, and microscopes.

2. Communication:

   • Fiber Optics: Uses materials with known refractive indices to control and transmit light efficiently.

By understanding the refractive index and speed of light, we can optimize systems for various practical applications.