Happy Grove, Titchfield, Seaforth, St.
Mary High & Annotto Bay High School
Physics Tutorial – Section C
June 2004, Paper III, Question #4
a) Describe an experiment to verify the laws of reflection. (8 marks)
b) Figure 5 is a magnified view of the cross section of one track of a compact disk (CD) and its
read head.
Information is stored on the CD as a series of 'hills' and 'valleys' stamped into the aluminium
mirror. The information is read by shining light from a laser source at X through the clear plastic
layer so that it is reflected towards the sensor at Y, which has a very tiny opening.
i) If the laser light beam follows the path shown in Figure 6, below, calculate the refractive
index of the clear plastic. (5 marks)
Mikhael V. Davis JP Revised: 12/4/2024
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Happy Grove, Titchfield, Seaforth, St. Mary High & Annotto Bay High School
Physics Tutorial – Section C
b) ii) The track moves to the left (read head does not move) so that EF becomes the reflecting
surface (see Figure 6). With the aid of a diagram showing the beam reflected from surface EF
through the plastic and into the air, explain why the emerging beam will miss the sensor.
(7 marks)
Total = 20 marks
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June 2008, Paper II, Question #5 – Section B
a) Describe an experiment to verify Snell’s law. State the apparatus used, your method, and the
results you would take to arrive at your conclusion. (6 marks)
b) Figure 4 shows a ray of light, XY, incident on a right-angled prism, PQR, of refractive index
1.5. The point of incidence on PR is such that the refracted ray inside the prism is incident on
PQ.
Mikhael V. Davis JP Revised: 12/4/2024
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Happy Grove, Titchfield, Seaforth, St. Mary High & Annotto Bay High School
Physics Tutorial – Section C
Figure 4
i. Calculate the angle of refraction at the boundary, PR.
ii. Given that the critical angle for the glass-air boundary, PQ, is 41.8o, deduce whether or not
there would be total internal reflection at this boundary. (9 marks)
Total = 15 marks
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June 1999, Paper III, Question #3
a) With the aid of ray diagrams explain the terms' refractive index’ and 'critical angle'. Draw a
ray diagram to show how a right-angled isosceles glass prism can be used to turn a ray of light
through 180o, and identify an optical instrument that utilises this property. (8 marks)
b) i) A ray of light travelling in water at a speed of 2.25 x 108 m s-1 strikes the water surface as
in Figure 1 below. Determine the refractive index of water and calculate the maximum angle
the beam can make with the normal if the light is to enter the air. (6 marks)
Mikhael V. Davis JP Revised: 12/4/2024
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Happy Grove, Titchfield, Seaforth, St. Mary High & Annotto Bay High School
Physics Tutorial – Section C
ii) The light source is replaced by a detector of light, and a ray of light is then shone on the
surface of the water from the air. Is there any angle of incidence at which no light enters the
water? Explain. (Speed of light in air = 3.00 x 10 m s-1) (3 marks)
c) Figure 2 shows three rays entering a specially shaped piece of glass called a prismatic
window. The angle of incidence of the two outer rays on the surfaces AB and CD is greater than
the critical angle for glass. Copy and complete the diagram to show the passage of the rays
through the window.
(3 marks)
Total = 20 marks
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January/June 2002 Specimen Paper, Paper II, Question #1
a) Define the term "refractive index" and give TWO examples of observations which show that
light can be refracted. (3 marks)
Mikhael V. Davis JP Revised: 12/4/2024
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Happy Grove, Titchfield, Seaforth, St. Mary High & Annotto Bay High School
Physics Tutorial – Section C
i) Draw a diagram, showing how a prism can split a beam of white light into its constituent
colours. On your diagram the relative positions of red and violet should be indicated.
ii) Explain why a converging lens is often placed in the path of the diverging beam emerging
from the prism.
iii) Use your answer to b) i) above to deduce how the wavelength of light is related to the
refractive index. (7 marks)
c)
Figure 1 shows an experiment in which a beam of laser light is initially incident at A on a rule.
A transparent slab is then placed in the path of the beam so that the angle of incidence on the slab
is 60o. The beam emerges at an angle, θ, to the normal to the slab.
i) Calculate the angle of refraction in the slab and the value of θ if the slab made of glass.
(Refractive index of glass = 1.5)
ii) y is the distance between the position of the undeviated beam and the position of the deviated
beam. State and explain the effect on y of using
a) a slab with a higher refractive index
b) laser light of longer wavelength (10 marks)
Total = 20 marks
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Mikhael V. Davis JP Revised: 12/4/2024
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Happy Grove, Titchfield, Seaforth, St. Mary High & Annotto Bay High School
Physics Tutorial – Section C
June 1994, Paper II, Question #3
a) Light and sound are both forms of waves. State TWO differences between light waves and
sound waves. (2 marks)
b) The diagram above shows a loudspeaker at the end of a room with an open door leading into
another room. A sound of frequency 255 Hz is emitted.
i) Draw ON THE DIAGRAM a representation of the sound wave emerging from the door. .
(2 marks)
ii) Why is someone standing at Point T able to hear the sound but not able to see the
loudspeaker? (3 marks)
iii) If the speed of sound is 340 m s-1, calculate the wavelength of the sound waves.
(3 marks)
c) In a storm the lightning is often seen a considerable time before the thunder is heard.
i) Account for this fact. (2 marks)
ii) If the lightning is seen 8 seconds before the thunder is heard, calculate the distance of the
thundercloud from the observer. (2 marks)
iii) What assumption have you made in your calculation in ii) above? (1 mark)
Total = 15 marks
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January 2010, Paper II, Question #3 – Section A
a) Two types of waves are longitudinal and transverse waves.
What is meant by the term ‘longitudinal wave’? (2 marks)
b) Figure 2 shows a wavetrain in which the points A to I and w to z are shown.
Mikhael V. Davis JP Revised: 12/4/2024
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Happy Grove, Titchfield, Seaforth, St. Mary High & Annotto Bay High School
Physics Tutorial – Section C
Figure 2. A Wavetrain
Identify, using two letters, the distance between any TWO points of the following in the
wavetrain:
i) a wavelength
ii) the amplitude of the wave (2 marks)
c) A slinky spring can be used to generate a transverse waveform. In the box below, draw and
label this waveform, clearly identifying
i) particle movement
ii) waveform movement
iii) at least one crest and one trough
Mikhael V. Davis JP Revised: 12/4/2024
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Happy Grove, Titchfield, Seaforth, St. Mary High & Annotto Bay High School
Physics Tutorial – Section C
(3 marks)
d) i) A steelpan produces a sound of frequency 0.350 kHz. The speed of sound on air is 340 m s-
1
. What is the wavelength of the sond generated by the steelpan? (4 marks)
ii) If this sound is generated under water instead, what is the frequency that would be detected?
(1 mark)
iii) The sound wave generated under water is refracted at the water-air boundary. Calculate the
refractive index of water, given that the wavelength of this sound in water is 1.29 m.
(3 marks)
Total = 15 marks
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May 2013, Paper II, Question #3, Section A
a) i) State Snell’s Law. (3 marks)
ii) In the space below, draw a labeled diagram using the converging lens to show clearly the
following features:
• Principal axis
• Principal focus
• focal length
• focal plane (4 marks)
b) i) Describe the path into a prism and out of a prism when a ray of light is incident at 900 to the
hypotenuse of a right-angled glass prism shown in figure 1.
Figure 1
(7 marks)
Mikhael V. Davis JP Revised: 12/4/2024
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Happy Grove, Titchfield, Seaforth, St. Mary High & Annotto Bay High School
Physics Tutorial – Section C
ii) Through what angle would the ray be turned after emerging? (1 mark)
(critical angle of glass = 420)
Total = 15 marks
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May 2014, Paper II, Question #4, Section B
a) State the laws of refraction. (6 marks)
b) Figure 3 shows the clown fish, Nemo, looking at point B. It sees the fisherman’s net appearing
as if it were at A.
Figure 3
i) Calculate angle c, given that angle ABD is 420C.
(3 marks)
ii) Given that angle c is the critical angle for the air water boundary, calculate the refractive
index of the water. (3 marks)
iii)
Figure 4
Nemo swims away and his eye is now a horizontal distance of 5 metres from point B. Looking at
point B he no longer sees the net but sees Bruce, the shark.
If Bruce is at the same depth as Nemo, how far away is Bruce’s eye from Nemo’s eye? Explain
your result. (3 marks)
Total = 15 marks
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Mikhael V. Davis JP Revised: 12/4/2024
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Happy Grove, Titchfield, Seaforth, St. Mary High & Annotto Bay High School
Physics Tutorial – Section C
June 1987, Paper III, Question #4
a) An object 4.0 cm high is placed perpendicular to the axis of a converging lens and 50 cm from
its centre. The focal length of the lens is 20 cm. By means of a scale drawing (on graph paper),
find the position of the image and its size. (9 marks)
b) i) We normally say that light travels in straight lines. As evidence for this belief, we note that
it casts clear shadows and does not appear to bend around corners. Does this mean that light
does not travel as a wave? Explain your answer. (3 marks)
ii) Describe how you would demonstrate in the laboratory that light does, in fact, have a wave
motion. (4 marks)
iii) Even after the wave motion of light had been demonstrated by Thomas Young, Newton’s
corpuscular (particle) theory still was accepted by many scientists. What crucial experiment did
Foucault perform and how did it settle the argument over the rival theories? (4 marks)
Total = 20 marks
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Mikhael V. Davis JP Revised: 12/4/2024
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