Question

Question 1: Answer, True or False

The index of refraction has units of distance.

True

False

When we make multiple measurements, we can have more confidence in the index of refraction determination.

True

False

Glass is more dense than water.

True

False

It is possible to exceed the speed of light in a vacuum

True

False

A tangent line is parallel to a normal line

True

False

The index of refraction is unitless.

True

False

There is a special case when the index of refraction is less than 1.

True

False

Answer 1

Solution-

1. The index of refraction has units of distance.- False

Reason- Refractive index has no units because the refractive index is the ratio of the speed of light in vacuum to the speed of light within the material and the, so the units cancel out and hence no units.

2. When we make multiple measurements, we can have more confidence in the index of refraction determination.- True

Reason- Averaged observations are better.

3. Glass is more dense than water. - True

Reason- Glass is the denser than water because the speed of light in glass is less than that of water and hence refractive index is higher for glass.

4. It is possible to exceed the speed of light in a vacuum- False.

Reason- According to the theory of relativity, the mass becomes negative if we try to achieve more than the speed of light. Since mass can't be negative hence, the statement is true.

5. A tangent line is parallel to a normal line- False

Reason- Normal is perpendicular to the tangent.

6. The index of refraction is unitless.- True

Reason- It is the ration of the speed of light in vacuum and speed of light in the medium. So units cancel out.

7. There is a special case when the index of refraction is less than 1. - True

Reason- The theory of relativity limits the group velocity to be less than the velocity of light. But in some cases, we can have phase velocity higher than the speed of light and hence in those cases refractive index can be less than 1