Worksheet 9
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This document contains a 14 question worksheet on waves and wave properties. It includes questions that assess understanding of wave concepts like amplitude, wavelength, frequency, intensity, and inverse square law relationships. Graphs and diagrams are provided that show wave displacement over time. Students are asked to analyze wave patterns, calculate wave properties, and apply equations to solve problems involving intensity, power, and distance relationships for waves including light and sound.
![14 Worksheet (AS)
Data needed to answer questions can be found in the Data, formulae and relationships sheet.
1 The diagram shows a graph of the displacement of a wave.
Displacement X
Time
What property of the wave is X? [1]
A amplitude
B frequency
C period
D wavelength
2 The graph shows the displacement of particles in a sound wave. Which distance, on the graph,
represents the amplitude of the wave?
[1]
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![14 Worksheet (AS)
3 Which of the following cannot be polarised? [1]
A infrared waves
B microwaves
C sound waves
D ultraviolet waves
4 Red light has a wavelength of 684 nm. What is its frequency? [1]
2
A 2.05 × 10 Hz
B 4.39 × 105 Hz
C 4.39 × 1014 Hz
D 2.05 × 1020 Hz
5 An oscilloscope is connected to a microphone. The diagram shows the trace displayed when a note
is played.
A note is played of half the amplitude and twice the frequency. The settings of the oscilloscope
remain unchanged. Which diagram shows the trace for this note? [1]
A B
C D
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![14 Worksheet (AS)
6 Calculate the frequency of the following waves:
a red light of wavelength 6.5 × 10−7 m emitted from a light-emitting diode [2]
b ultrasound of wavelength 7.0 mm emitted by a bat. [2]
7 In a water tank, a dipper oscillating at a frequency of 30 Hz produces surface water waves of
wavelength 2.5 cm.
a Calculate the speed of the water waves. [2]
b Determine the wavelength of the waves when the frequency of the dipper is doubled. [2]
8 The graph shows the displacement of particles in a sound wave.
a Calculate:
i the period of the wave [2]
ii the frequency of the wave. [1]
b On a copy of the diagram draw a wave of the same frequency but four times the intensity. [1]
9 An oscilloscope has its time-base and Y-sensitivity (Y-gain) set on 0.5 ms cm−1 and 0.5 V cm−1,
respectively. A person whistles into a microphone connected to the oscilloscope. The trace
displayed on the oscilloscope screen is shown below.
a Determine the frequency of the sound wave. [2]
b Calculate the wavelength of the sound produced by the whistle. [2]
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![14 Worksheet (AS)
10 You can use the following equation to determine the intensity of a wave:
power
intensity =
cross - sectional area
This equation can be applied to all waves, including sound.
The intensity of sound at a certain distance from a loudspeaker is 3.5 × 10−3 W m−2.
The amplitude of the sound waves at this point is known to be 0.45 mm. Calculate:
a the power transmitted through a cross-sectional area of 8.0 × 10−5 m2 when the intensity
of sound is 3.5 × 10−3 W m–2 [2]
b the intensity of sound where the amplitude is 0.90 mm [3]
c the amplitude of the sound waves where the intensity is 5.6 × 10−2 W m−2. [3]
11 The intensity of a wave may be defined as the power transmitted per unit cross-sectional area at
right angles to the direction of travel.
a For a point source of light, explain why the intensity I at a distance r away from the source
obeys an inverse square law with distance, that is:
1
I∝ . [3]
r2
b The intensity of visible light from the Sun reaching the upper parts of our atmosphere is
about 1.4 kW m−2. The Sun has a radius of 7.0 × 108 m and is 1.5 × 1011 m from the Earth.
Calculate:
i the intensity of visible light emitted from the Sun’s surface [3]
ii the total power radiated by the Sun in the visible region of the electromagnetic
spectrum [2]
iii the intensity of light from the Sun at the planet Neptune.
(Neptune is 4.5 × 1012 m from the Sun.) [3]
Total: Score: %
40
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Worksheet 9
- 1. 14 Worksheet (AS) Data needed to answer questions can be found in the Data, formulae and relationships sheet. 1 The diagram shows a graph of the displacement of a wave. Displacement X Time What property of the wave is X? [1] A amplitude B frequency C period D wavelength 2 The graph shows the displacement of particles in a sound wave. Which distance, on the graph, represents the amplitude of the wave? [1] AS and A Level Physics Original material © Cambridge University Press 2010 1
- 2. 14 Worksheet (AS) 3 Which of the following cannot be polarised? [1] A infrared waves B microwaves C sound waves D ultraviolet waves 4 Red light has a wavelength of 684 nm. What is its frequency? [1] 2 A 2.05 × 10 Hz B 4.39 × 105 Hz C 4.39 × 1014 Hz D 2.05 × 1020 Hz 5 An oscilloscope is connected to a microphone. The diagram shows the trace displayed when a note is played. A note is played of half the amplitude and twice the frequency. The settings of the oscilloscope remain unchanged. Which diagram shows the trace for this note? [1] A B C D AS and A Level Physics Original material © Cambridge University Press 2010 2
- 3. 14 Worksheet (AS) 6 Calculate the frequency of the following waves: a red light of wavelength 6.5 × 10−7 m emitted from a light-emitting diode [2] b ultrasound of wavelength 7.0 mm emitted by a bat. [2] 7 In a water tank, a dipper oscillating at a frequency of 30 Hz produces surface water waves of wavelength 2.5 cm. a Calculate the speed of the water waves. [2] b Determine the wavelength of the waves when the frequency of the dipper is doubled. [2] 8 The graph shows the displacement of particles in a sound wave. a Calculate: i the period of the wave [2] ii the frequency of the wave. [1] b On a copy of the diagram draw a wave of the same frequency but four times the intensity. [1] 9 An oscilloscope has its time-base and Y-sensitivity (Y-gain) set on 0.5 ms cm−1 and 0.5 V cm−1, respectively. A person whistles into a microphone connected to the oscilloscope. The trace displayed on the oscilloscope screen is shown below. a Determine the frequency of the sound wave. [2] b Calculate the wavelength of the sound produced by the whistle. [2] AS and A Level Physics Original material © Cambridge University Press 2010 3
- 4. 14 Worksheet (AS) 10 You can use the following equation to determine the intensity of a wave: power intensity = cross - sectional area This equation can be applied to all waves, including sound. The intensity of sound at a certain distance from a loudspeaker is 3.5 × 10−3 W m−2. The amplitude of the sound waves at this point is known to be 0.45 mm. Calculate: a the power transmitted through a cross-sectional area of 8.0 × 10−5 m2 when the intensity of sound is 3.5 × 10−3 W m–2 [2] b the intensity of sound where the amplitude is 0.90 mm [3] c the amplitude of the sound waves where the intensity is 5.6 × 10−2 W m−2. [3] 11 The intensity of a wave may be defined as the power transmitted per unit cross-sectional area at right angles to the direction of travel. a For a point source of light, explain why the intensity I at a distance r away from the source obeys an inverse square law with distance, that is: 1 I∝ . [3] r2 b The intensity of visible light from the Sun reaching the upper parts of our atmosphere is about 1.4 kW m−2. The Sun has a radius of 7.0 × 108 m and is 1.5 × 1011 m from the Earth. Calculate: i the intensity of visible light emitted from the Sun’s surface [3] ii the total power radiated by the Sun in the visible region of the electromagnetic spectrum [2] iii the intensity of light from the Sun at the planet Neptune. (Neptune is 4.5 × 1012 m from the Sun.) [3] Total: Score: % 40 AS and A Level Physics Original material © Cambridge University Press 2010 4