Sound (Edexcel GCSE Physics)

The diagram in Figure 7 shows two students, P and Q, trying to measure the speed of sound in air.

Figure 7

P will clap his hands together.

When Q sees P clap his hands, she will start a timer.

When Q hears the clap, she will stop the timer.

Explain one way the students could improve their method.

Higher Tier Only

Figure 8 shows a long metal rod and a hammer.

The rod is hit at one end by the hammer.

This causes a sound wave to travel along the inside of the metal rod.

Figure 8

Describe how hitting the rod causes a sound wave to travel along the inside of the rod.

Sound travels slower in air than it does in water.

Figure 9 shows the direction of travel of a sound wave approaching a boundary between air and water.

The sound wave refracts at the boundary between air and water.

Figure 9

Complete the diagram in Figure 9 to show the direction the sound wave travels in the air.

Sound travels slower in cold air than it does in warm air.

The equation relating the speed of sound in air to the density of the air is

      where K is a constant.

The table in Figure 10 gives some data about the speed of sound in air and the density of air.

Figure 10

Use the equation and the data in the table in Figure 10 to calculate the speed of sound in warm air.

Give your answer to an appropriate number of significant figures.

speed of sound in warm air = ................................... m/s

Higher Tier Only

Sonar is an example of a use of ultrasound.

State one other example of a use of ultrasound.

Higher Tier Only

State an example of a use of infrasound.

Higher Tier Only

Figure 1 shows the depth of the sea, measured using sonar, at different distances from the shore.

Figure 1

A technician on a boat uses sonar pulses to measure the depth of the sea when the boat is 120 m from the shore.  

Calculate the total time of travel for the sonar pulse used to make this measurement.  

The speed of the sonar pulse in seawater is 1600 m/s.

time of travel = .................................................. s

Higher Tier Only

Figure 14 shows the hearing responses of a human, a mouse and a bird over a range of frequencies of sound.

Figure 14

i) Describe two differences between the hearing responses of the human and the mouse.

[2]

ii) A farmer wants to use an alarm to scare away these birds.

State which frequency would be most effective.

Give the appropriate units.

frequency ...................................................[1]

iii) State the reason for your choice of frequency in (ii).

[1]

Higher Tier Only

 Describe the difference between ‘infrasound’ and ‘ultrasound’.

Higher Tier Only

A transducer can transmit and detect ultrasonic waves.

Figure 15 shows ultrasonic waves transmitted by the transducer on the bottom of a ship.

Figure 15

The waves reflect off the sea floor and are received back at the transducer.

The waves travel at 1500 m/s.

The time between transmission and reception is 48 milliseconds.

Calculate the depth of water, D, shown in Figure 15.

depth of water, D = ................................................ m

Explain how vibrations from earthquakes may be used to study the core of the Earth.

Higher Tier Only

Figure 1 shows a sound wave.

Figure 1 (not to scale)

On the wave shown in Figure 1: 

(i) Mark the centre of a compression with an X.

[1]  

(ii) Mark the centre of a rarefaction with a Y.

[1]

Higher Tier Only

Describe how a human could hear a sound wave such as the one shown in Figure 1.

Higher Tier Only

State the frequencies between which the human ear can detect sound.

Higher Tier Only

Ultrasound has a frequency above the range of human hearing.

State one similarity between a sound wave and an ultrasound wave.

Which of the following waves is longitudinal?

Which row in the table correctly describes what happens to a sound wave that travels from air to water?

Sound waves travel faster through solids than liquids or gases.

Explain why sound waves travel faster in solids.

Higher Tier Only

Sound waves oscillate in the same direction as the direction of energy transfer.

State two other examples of longitudinal waves.

Higher Tier Only 

This question is about ultrasound.

Which of these is a frequency of ultrasound?

Higher Tier Only

Ultrasound has many uses.

i) One device called a pest repeller emits ultrasound.

The ultrasound keeps mice out of the garden.

Explain why the device affects mice but does not affect humans.

[2]

ii) A technician has a different ultrasound device.

This device can emit and detect short pulses of ultrasound.

The device can also measure the time, in ms, from emitting a pulse to detecting the same pulse.

Describe how the technician can use this device to determine the speed of ultrasound in air.

[3]