Name:________________________ Class:_____________(_______)
S3/PHY/HW
HKUGA College
S.3 Physics – Homework
Chapter 18 Refraction of light
/22
MC (Fill in the answer in the boxes.)
1. The figure below show a light ray entering medium Y 4. A horizontal light ray is incident on a glass prism.
from medium X. Which of the following ray diagrams is correct?
A. B.
Which statement(s) is/are correct?
C. D.
(1) The light travels faster in medium X.
(2) is the angle of refraction.
(3) Medium X can be water while medium Y is air.
A. (1) only
B. (3) only
C. (1) and (2) only
D. (2) and (3) only 5. A diver is looking at a helicopter that stays still in air.
Which position best shows the apparent position of the
2. A light ray passes from air into water (refractive helicopter?
index 1.33).What is the angle between the reflected ray
and refracted ray?
A. 97
B. 105
C. 111
D. 117
3. 57°
medium A
medium B Answer Box (1.5 marks each)
38°
1 2 3 4 5
A light ray travels from media A to B as shown. What is
the ratio of refractive indices in media A to that of B?
A. 3: 2
B. 2:3
C. sin 57° : sin 38°
D. sin 38° : sin 57°
1
Name:________________________ Class:_____________(_______)
S3/PHY/HW
Structural Question
1. The graph below shows a ray of light passing through two layers of liquids, water and carbon disulphide, each of
depth 5 cm, in a tank. The refractive indices of water and carbon disulphide are 1.33 and 1.63 respectively.
Find the angles 𝛼, 𝛽, 𝛾, 𝛿 and 𝜃. (5 marks)
2. A ray of light passes through a triangular plastic prism as shown. The ray strikes the side PQ at an angle of 50°.
(a) Find the angle of incidence when the light ray strikes the side PQ. (1 mark)
(b) Find the refractive index of the plastic. (2 marks)
(c) Sketch the path of the light ray travelling out of the prism and mark the angles on the diagram. (2 marks)
2
Name:________________________ Class:_____________(_______)
S3/PHY/HW
3.BONUS QUESTION
The refractive index of glass varies with the colour of light.
Refractive index of glass for red light = 1.513
Refractive index of glass for violet light = 1.532
A ray of white light is incident on side AB of a rectangular glass block, as shown below.
The red light and violet light from the incident ray arrive at slightly different points on side CD.
(a) Determine the distance between these points. (2.5 marks)
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(b) White light is incident on a boundary between glass and air, as shown below.
Explain what happens to the red light and the violet light when
meeting the boundary. Your answer should include
calculations. (2 marks)
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