11. Refractive Index

Question 1

What happens when light enters an optically denser material?

Answer 1

The light slows down

Question 2

What is the optical density of a material measured by?

Answer 2

Its refractive index

Question 3

What is the relationship between a material’s optical density and the refractive index?

Answer 3

The higher the material’s optical density, the higher the refractive index

Question 4

Define the term absolute refractive index

Answer 4

The ratio between the speed of light in a vacuum and the speed of light in that material

Question 5

What is the equation for finding the refractive index?

Answer 5

n = c / speed of light in substance

n = refractive index of material
c = 3.00 x 10^8 (m/s)

Question 6

Define the term relative refractive index

Answer 6

The ratio between the speed of light in material 1 to the speed of light in material 2

Question 7

What is the angle of incidence?

Answer 7

The angle that incoming light makes to the normal

Question 8

What is the angle of refraction?

Answer 8

The angle that the refracted ray makes to the normal

Question 9

What is Snell’s law of refraction for a boundary between two materials?

Answer 9

n1 sin θ1 = n2 sin θ2

n1 = refractive index of material 1
θ1 = angle of incidence of ray in material 1
n2 = refractive index of material 2
θ2 = angle of refraction of ray in material 2

Question 10

What happens when n1 is less than n2?

Answer 10

θ1 > θ2

Question 11

What happens when n1 is greater than n2?

Answer 11

θ1 < θ2