Part B: Matching (8 marks K) Match the term on the left with the correct label from the diagram on the
right. Not all letters in the diagram will be used.
1. F angle of incidence
2. I angle of refraction
n
3. B medium in which light travels more slowly
4. N normal
5. M boundary between media
6. D index of refraction of the “fast” medium
7. E incident ray
8. L refracted ray
Part B: Short Answer (11 marks C)
𝑛=
𝑐
𝑣
Medium
Air (vacuum)
Water
Vegetable Oil
Glass
Speed of light (m/s)
3.0 x 108
2.26 x 108
2.04 x 108
1.97 x 108
Critical Angle
--48.8o
42.9o
42.1o
1. Draw the refracted ray in each diagram. (2 marks)
a.
b.
Water
Air
Vegetable Oil
Glass
2. a) In which scenario above could total
internal reflection occur? Explain how you
know.
(2 marks)
b) Using your answer from 2a, sketch the
diagram showing the location of the
refracted ray at the critical angle. Include any
other ray(s) that occur.
(2 marks)
Vegetable Oil
GLASS TO VEG OIL because light is
speeding up from medium 1 to medium 2
(light will bend toward boundary of media).
Glass
Refracted ray
reflected ray
3. Give an example where light undergoes partial reflection and refraction at the same time. Briefly
explain the “partial reflection” and the “refraction” that is occurring in this example. (2 marks)
Two – way mirror, mirrored sunglasses
Partial reflection = one side looks like a mirror
Refraction = you can see through the other side
4. The index of refraction in arsenic trisulfide glass is 2.04. What is the speed of light in this medium?
Use GRASS! (3 marks)
G: c = 3.0 x 108 m/s
N = 2.04
S: v = 3.0x 108 / 2.04
V = 1.47 x 108
R: v of arsenic trisulfide
S: The speed of light in arsenic trifluoride
A: n = c/v ------> v = c/n
is 1.47 x 108 m/s