Question

Which material will refract light the least? n = 1.72 n = 2.34 n = 1.58 n = 1.92 I think the answer is n = 1.58 but I need to know why a low index of refraction makes light move slower because I thought a low n would make light move faster in the medium.

Answer 1

Materials with a lower index of refraction refract light less and allow light to move faster through them. The material with an index of refraction of 1.58 will refract light the least amongst the options given. Light is fastest in air and slowest in glass among the examples provided.

Step-by-step explanation:

The index of refraction (n) of a material is defined as the ratio of the speed of light in a vacuum (c) to the speed of light in that material (v). It is given by the equation n = c/v. The higher the index of refraction, the slower the speed of light in the material. To answer the student's original question, the material with the lowest index of refraction (n = 1.58) will refract light the least, meaning that light travels faster through this material compared to those with higher indices of refraction.

Comparing the indices of refraction given for glass (1.52), air (1.0003), and water (1.333), we can arrange these materials by the speed of light from fastest to slowest as follows: air (fastest), water, and glass (slowest). This is because air has the closest index of refraction to that of a vacuum (n=1), which corresponds to the speed of light being fastest in air and slower in water and glass respectively.

Answer 2

Yes you're right. The smaller 'n' is, the faster the speed of light in THAT medium.
In empty space vacuum, where the speed of light is fastest, n=1 exactly. In any material medium, 'n' is bigger than 1, and the bigger it is, the slower the speed of light in that medium.
The amount of refraction depends on the CHANGE of speed at the boundary. So when light goes from air or vacuum into, say, the 2.34, there's a big change of speed, and more refraction. But from space or air into 1.58, less change of speed, and less refraction.
If the light is going from a block of 1.58 into a block of 1.72, then not much refraction, because not much CHANGE in speed.