Refraction and Optical Density Lecture Notes

Flashcards covering the definitions of reflection, speed of light in various media, and the concepts of optical density versus physical density.

What is the definition of reflection of light?

The return of light in the same medium after striking a polished surface.

What are the two laws of reflection?

(i) the angle of reflection is equal to the angle of incidence, and (ii) the incident ray, the normal at the point of incidence and the reflected ray, all lie in one plane.

What is the constant speed of light in vacuum and air?

$$3 \times 10^8\,m\,s^{-1}$$

What is the speed of light in water?

$$2.25 \times 10^8\,m\,s^{-1}$$

What is the speed of light in glass?

$$2 \times 10^8\,m\,s^{-1}$$

Under what condition is a second medium considered optically denser than the first?

If light slows down while passing from the first medium into the second medium.

Under what condition is a second medium considered optically rarer than the first?

If light speeds up while passing from the first medium into the second medium.

How does the optical density of air compare to water and glass?

Air is optically rarer than water and glass.

Between glass and water, which medium is optically denser?

Glass is optically denser than water.

Using kerosene and water as an example, how does physical density relate to optical density?

Kerosene is less dense than water (it floats on water), but it is optically denser than water.

What physical property determines the optical density of a medium?

The speed of light in that medium.

What physical property determines the density of a medium?

Inter-molecular separation.