What is the index of refraction of glass if light travels through the glass at a speed of 133,000 mi/sec?

To determine the index of refraction of a material, such as glass, it's essential to understand the relationship between the speed of light in a vacuum and the speed of light in that material. The index of refraction (n) is calculated using the formula:

n = c / v,

where:

• c is the speed of light in a vacuum (approximately 299,792,458 meters per second or about 186,282 miles per second),

• v is the speed of light in the material, which in this case is given as 133,000 miles per second.

First, it’s necessary to convert the speed from miles per second to a uniform metric system, or directly calculate the index of refraction using the speeds given in miles per second:

1. Calculate the index of refraction:

n = c / v

n = 186,282 miles/sec / 133,000 miles/sec ≈ 1.4.

Based on this calculation, the value closest to this result among the provided options is indeed 1.398, which reflects the correct index of refraction for this scenario.

This understanding showcases how the physical properties of light interacting with materials result in different indices of refraction, which helps in