2.18 refraction

Question 1

what is refractive index a measure of?

Answer 1

how easy light can travel through it.

Question 2

how is refractive index calculated?

Answer 2

n=c/v
n is refractive index
c=speed of light in vacuum
v=speed of light in the material

Question 3

what does it mean if the refractive index of a material is 1?

Answer 3

material allows light to travel at the same speed as air

Question 4

what does a higher refractive index mean?

Answer 4

the material is denser and light travels slower

Question 5

what happens to a ray of light as it enters a denser material?

Answer 5

slower speed

bends towards the normal

Question 6

what happens to a ray of light as it enters a less dense material?

Answer 6

faster, bends away from normal

Question 7

what example is usual to imagine when figuring out how a ray acts when it diffracts?

Answer 7

think of the ray as a car driving through road to mud or mud to road and how the speed of the tires in each means it changes direction

Question 8

what happens when the angle a light ray hits a boundary at is less than the critical angle?

Answer 8

the light refracts into the second material (there is some reflection)

Question 9

what happens when the angle a light ray hits a boundary at is the same as the critical angle?

Answer 9

the light ray is bent along the boundary between the two materials

Question 10

what happens when the angle a light ray hits a boundary at is bigger than the critical angle?

Answer 10

total internal reflection

Question 11

what is total internal reflection?

Answer 11

when a light ray hits a boundary at more than the critical angle, the light ray is reflected backwards and the same angle from the normal it went in with

Question 12

how would you find the critical angle?

Answer 12

when one of the materials is air

n=1/sin(incident angle)

Question 13

describe 2 uses for optical fibres

Answer 13

communication wires

medical endoscopes-as they are flexible.