Properties of Waves Practice Questions

Question 1

5 marks

A duck is floating on the surface of a pond. A boy throws a stone into the water some distance away. Ripples spread out across the pond and pass the duck.

(a)

Complete the sentence.

Waves transfer .............................. and .............................. from one place to another without transferring .............................. .

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(b)

As the ripples pass, the duck bobs up and down but stays in the same place on the pond.

Explain what this shows about water waves.

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(c)

Describe one piece of evidence that shows air does not travel from place to place when a sound wave travels through it.

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Question 2

4 marks

Figure 1 shows a wave travelling along a stretched rope at one instant. The side of each square on the grid represents 1 cm.

(a)

Use the grid to find the wavelength of the wave.

wavelength = .............................................................. cm

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(b)

Use the grid to find the amplitude of the wave.

amplitude = .............................................................. cm

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(c)

State what is meant by the frequency of a wave.

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Question 3

5 marks

Waves can be described as transverse or longitudinal.

(a)

Which of these is a longitudinal wave?

Tick one box.

☐ a ripple on the surface of water

☐ a light wave

☐ a sound wave in air

☐ a seismic S-wave

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(b)

Describe the difference between a longitudinal wave and a transverse wave.

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(c)

A loudspeaker produces a sound wave in air.

Name the region of the sound wave where

(i) the air particles are pushed closest together

(ii) the air particles are furthest apart.

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Question 0

6 marks

A student uses a ripple tank to measure the speed of ripples on the surface of water. A motor makes a straight dipper vibrate, and a lamp above the tank produces an image of the ripples on a white screen below the tank.

(a)

Describe how the student can obtain an accurate value for the wavelength of the ripples.

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(b)

The dipper produces 30 ripples in 10 s.

Calculate the frequency of the ripples.

frequency = .............................................................. Hz

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(c)

The wavelength of the ripples is 2.4 cm.

Calculate the speed of the ripples.

Give your answer in m/s.

speed = .............................................................. m/s

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(d)

Suggest why the wavelength measured on the screen may be larger than the true wavelength of the ripples in the tank.

/ 1

Question 0

7 marks

A survey ship uses a sonar system to find the depth of water below it. The ship sends a pulse of sound straight down towards the seabed. The reflected pulse is detected 0.36 s after the pulse was sent out.

The speed of sound in seawater is 1500 m/s.

(a)

Explain why the depth of the water is not calculated using the full 0.36 s.

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(b)

Calculate the depth of the water below the ship.

Use the equation

$\text{distance} = \text{wave speed} \times \text{time}$

depth = .............................................................. m

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(c)

The reflected pulse detected by the ship is much weaker than the pulse that was sent out.

Give two reasons for this.

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(d)

Sonar systems used in very deep water use sound of a longer wavelength, because less of this sound is absorbed by the seawater.

State what this shows about the absorption of waves by a substance.

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Question 0

7 marks

Figure 2 shows waves in the sea travelling towards a sandbank. The water over the sandbank is much shallower than the water in front of it. The wavefronts reach the edge of the sandbank at an angle.

In the deep water the waves travel at 6.0 m/s and have a period of 5.0 s.

(a)

Calculate the frequency of the waves in the deep water.

frequency = .............................................................. Hz

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(b)

Calculate the wavelength of the waves in the deep water.

Use the equation

$\text{wave speed} = \text{frequency} \times \text{wavelength}$

wavelength = .............................................................. m

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(c)

Over the sandbank the waves slow down to 3.6 m/s. The frequency of the waves does not change.

Calculate the wavelength of the waves over the sandbank.

wavelength = .............................................................. m

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(d)

Explain why the direction in which the waves are travelling changes at the edge of the sandbank.

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Question 0

5 marks

Two students measure the speed of sound in air on a school field. Student A stands 200 m from student B and bangs two blocks of wood together. Student B starts a stopwatch when she sees the blocks hit each other and stops it when she hears the sound.

The results are shown in the table.

Trial	Time / s
1	0.62
2	0.58
3	0.60

(a)

Calculate the mean time taken for the sound to travel 200 m.

mean time = .............................................................. s

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(b)

Calculate the speed of sound obtained from these results.

Use the equation

$\text{wave speed} = \frac{\text{distance}}{\text{time}}$

speed of sound = .............................................................. m/s

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(c)

The accepted value for the speed of sound in air is 340 m/s.

Suggest one reason why this method does not give an accurate value, and describe one way the students could improve the method.

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Question 0

5 marks

An earthquake produces seismic P-waves that travel through rock. A P-wave has a period of 0.50 s.

(a)

State what is meant by the period of a wave.

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(b)

Calculate the frequency of the P-wave.

frequency = .............................................................. Hz

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(c)

The P-wave travels through the rock at 6000 m/s.

Calculate the wavelength of the P-wave.

Use the equation

$\text{wave speed} = \text{frequency} \times \text{wavelength}$

wavelength = .............................................................. m

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Question 0

6 marks

A student is asked to measure the speed of sound in air. The following equipment is available:

a signal generator and a loudspeaker
two microphones connected to a double-beam oscilloscope
a metre rule
a stopwatch

Describe how the student could use this equipment to obtain an accurate value for the speed of sound in air.

Your answer should include an evaluation of the suitability of the equipment. (6)

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Question 0

7 marks

An engineer checks a steel rail for cracks. A probe at one end of the rail sends a short pulse of sound along the rail and detects any pulses that come back to the same end.

The speed of sound in steel is 5900 m/s.

Two reflected pulses are detected: the first 1.2 ms after the pulse was sent, and the second 4.0 ms after the pulse was sent.

(a)

Calculate the length of the rail.

length = .............................................................. m

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(b)

Calculate the distance of the crack from the probe.

distance = .............................................................. m

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(c)

Explain why a pulse is detected from the far end of the rail as well as from the crack.

/ 2

Key Concepts of Physics

Motion & Forces

Conservation of Energy

Waves

Light & the Electromagnetic Spectrum

Radioactivity

Astronomy

Energy – Forces Doing Work

Forces & their Effects

Electricity & Circuits

Static Electricity

Magnetism & the Motor Effect

Electromagnetic Induction

Particle Model

Forces & Matter

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