Sound waves

This question is about sound waves.

Which range of frequencies of sound waves can be heard by humans?

The table gives some statements about sound waves.

Complete the table by placing a tick () next to each correct statement.

An oscilloscope can be used to display a sound wave.

Give the name of the variable that is measured on the x‑axis of the oscilloscope screen.

The diagram shows the trace on an oscilloscope screen when a sound wave is detected.

On the screen, draw the trace for a quieter sound wave with a lower frequency.

A high‑frequency sound wave is detected by a microphone and displayed on an oscilloscope.

The diagram shows the oscilloscope screen when the sound wave is detected. It also shows the oscilloscope settings.

Give the maximum frequency of sound that can be heard by humans.

Determine if the sound wave displayed on the oscilloscope could be heard by humans.

A student changes the settings of the oscilloscope to alter the displayed wave in these two ways.

• increase the amplitude of the wave

• only display one time period of the wave on the screen

The table shows some possible settings for the oscilloscope.

Which row of the table gives the student’s new oscilloscope settings?

A student investigates the speed of sound by making a loud sound in front of a large wall a long distance away.

The diagram shows the positions of the student and the wall.

The sound reflects off the wall and back to the student.

Give an appropriate method for measuring the distance between the student and the wall.

The student uses a stopwatch to determine the time taken for the sound to travel from them to the wall and back again.

The distance from the student to the wall is 65 m.

The student measures a time of 0.35 seconds when the sound has travelled to the wall and back again.

Calculate the speed of sound from the student’s data.

Evaluate this method for determining an accurate value for the speed of sound.

Explain an improvement to the student’s method.

This question is about sound.

State which wave property determines the pitch of a sound.

The bar chart shows the maximum frequency of sound heard by four animals and

Explain which of the bars is most likely to show the results for a human.

A sound wave has a frequency of 500 Hz.

Show that the time period of the sound wave is 2.0 ms.

The diagram shows the screen of an oscilloscope.

The timebase of the oscilloscope is 0.50 ms per square.

Draw the trace on the oscilloscope screen when the sound wave is detected.

The diagram shows two students doing an experiment to measure the speed of sound in air.

• both students stand 100 m away from a large flat wall

• student A makes a sound by hitting two blocks of wood together

• the sound waves travel to the wall and reflect back to the students as an echo

• student A hits the blocks together again when the echo is heard

• student A continues to hit the blocks together every time an echo is heard

• student B starts a timer when the blocks are hit together and stops the timer when the blocks have been hit together 20 more times

Give a reason why the students do not stand nearer to the wall.

The students repeat their method five times.

The table shows the students’ results.

The students decide that one of their tests shows an anomalous result.

Circle the anomalous result in the table.

Suggest a reason for the anomalous result.

Calculate the mean time between starting and stopping the timer.

Give your answer to a suitable number of decimal places.

The speed of sound in air can be calculated using the formula

Use the students’ results to calculate a value for the speed of sound in air.

An oscilloscope can be used to determine the frequency of a sound wave.

Give the name of the piece of apparatus that must be connected to the oscilloscope to detect the sound wave.

The diagram shows the screen of the oscilloscope and the oscilloscope settings.

A sound wave of frequency 250 Hz is detected.

The sound wave produces a trace on the oscilloscope of amplitude 4 V.

Complete the diagram by drawing the trace of this sound wave on the oscilloscope screen.

The graph shows how the wavelength of sound waves in air varies with their frequency.

If wavelength and frequency are inversely proportional, then

wavelength × frequency = constant

Using the graph, evaluate whether the wavelength of sound waves in air is inversely proportional to their frequency.

The diagram shows the screen of an oscilloscope when a sound wave is detected, and the oscilloscope settings.

Give the name of the piece of equipment that is connected to the oscilloscope to detect the sound wave.

Use the trace on the oscilloscope to determine the time period of the detected sound wave.

Calculate the frequency of the detected sound wave.

State the formula linking energy transferred, charge and voltage.

The effective voltage of the oscilloscope trace can be calculated using the formula

Use the effective voltage to calculate the energy transferred when 6.3 × 10⁻⁵C of charge passes through the oscilloscope.

This question is about sound waves.

The table gives the frequencies of some different sound waves.

Place ticks () in the table to show which sound waves can be heard by humans.

The diagram shows the screen of an oscilloscope when a sound wave is detected.

Add to the diagram by drawing the trace of another sound wave that has a lower pitch and is quieter than the sound wave shown.

The speed of sound in air varies with temperature.

A student finds a formula in a textbook that links the speed of sound waves in air to the temperature of the air, measured in kelvin.

speed of sound in air = (0.606×temperature in kelvin) + 166

Calculate the speed of sound when the air temperature is 46 °C.

Calculate the wavelength of a sound wave with a frequency of 15 000 Hz when the air temperature is 46 °C.

A student uses this method to investigate the speed of sound in air.

• set up an oscilloscope to detect and display a sound wave

• use a computer and a speaker to produce a sound of known wavelength

• use the oscilloscope to determine the frequency of the sound wave

• use a formula to calculate the speed of sound

Give the name of the equipment that should be connected to the oscilloscope to detect the sound wave.

The diagram shows the oscilloscope screen and the oscilloscope settings.

Oscilloscope settings

y direction: 1 square = 5 mV

x direction: 1 square = 0.5 ms

Determine the frequency of the sound wave.

The wavelength of the sound wave is 27 cm.

Calculate the speed of sound.

Describe how the oscilloscope could be adjusted to show fewer wave cycles on the screen.

Diagram 1 shows a simple loudspeaker.

The coil is connected to an alternating current (a.c.) supply.

Describe how the loudspeaker produces sound.

Diagram 2 shows two loudspeakers connected in series with a variable resistor.

The variable resistor is set to 5.0 Ω.

The total voltage across the two loudspeakers is 0.75 V and the current in the circuit is 0.15 A.

Show that the total power of the two loudspeakers is about 0.1 W.

[power = current × voltage]

A student varies the resistance of the variable resistor.

The table shows the power of the loudspeakers for different resistance values of the variable resistor.

Plot the student’s results on the grid.

Draw a curve of best fit.

Diagram 3 shows the loudspeakers connected in series to a cell.

Diagram 4 shows the loudspeakers connected in parallel to the same cell.

Comment on how the total resistance of the loudspeakers in diagram 3 compares with the total resistance of the loudspeakers in diagram 4.

Describe an investigation to determine the speed of sound.

You may draw a diagram to help your answer.

A microphone is connected to an oscilloscope.

A sound is detected by the microphone.

The diagram shows the oscilloscope trace.

Determine the period of the sound wave.

Calculate the frequency of the sound wave.

The diagram shows a fishing boat fitted with a high frequency sound wave emitter.

The boat is above some fish.

The high frequency sound waves travel from the emitter to the fish and then back to the emitter, where they are detected.

Name the wave behaviour that causes the sound waves to change direction when they reach the fish.

The table gives some data about the sound waves used.

Calculate the distance between the sound wave emitter and the fish.

High frequency sound waves decrease in amplitude as they travel through soft tissue in the human body.

The graph shows this decrease in amplitude for three different high frequency sound waves.

Estimate the distance travelled by a 2 MHz wave when its amplitude is 25% of its original value.

Describe what the graph shows about the penetrating ability of high frequency sound waves as they travel through soft tissue.

Two students do an experiment to measure the speed of sound in air.

They use two blocks of wood that make a loud noise when hit together.

They do their experiment outside in a wide‑open space.

Describe how the students should use their equipment to measure the speed of sound in air.

You may draw a diagram to support your answer.

The table shows the students’ results.

Calculate the mean time for the last row in the table.

The students think that some of their time readings are anomalous.

State how the students should deal with these anomalous readings.

Explain which distance in the table is likely to give the most accurate value for the speed of sound in air.

Magnetic Resonance Imaging (MRI) machines can take scans of the inside of a patient.

There is an electromagnet inside the MRI machine.

Describe the construction of an electromagnet.

You may draw a diagram to help your answer.

During the scan, music can be played through a loudspeaker to the patient.

The oscilloscope trace in the diagram represents a sound played to the patient.

Determine the period of the sound wave.

Calculate the frequency of the sound wave.

Deduce whether humans can hear the sound wave.

The current in the loudspeaker is alternating current (a.c.).

Give the evidence from the oscilloscope trace to support this statement.

Draw the circuit symbol for an a.c. power supply.

The diagram shows the construction of a simple loudspeaker.

A coil of wire is wrapped around a paper tube attached to the loudspeaker cone.

When there is an alternating current (a.c.) in the coil, the cone moves.

Explain how the loudspeaker produces a sound wave.

The photograph shows an oscilloscope.

An oscilloscope can be used to determine the frequency of a sound wave.

Name the piece of equipment that should be used with an oscilloscope to detect a sound wave.

Describe how an oscilloscope can be used to measure the time period of a sound wave.

Diagram 1 shows an oscilloscope screen when a sound wave is detected.

It also shows the settings of the oscilloscope.

Determine whether the sound can be heard by humans.

Include a calculation of frequency in your answer.

The oscilloscope settings are changed, as shown in Diagram 2.

On Diagram 2, draw the wave that would be displayed on the oscilloscope screen if the same sound wave is detected using these new settings.

The photograph shows a security camera.

The camera detects light waves and sound waves.

State two differences between light waves and sound waves.

The camera detects infrared waves, which allow the camera to record videos in the dark.

Which of these electromagnetic waves has a longer wavelength than infrared waves?

Which of these is another use for infrared waves?

Which of these is a harmful effect of infrared waves?

The grid shows the oscilloscope trace for a quiet, low‑pitch sound wave.

The security camera has an alarm that produces a loud, high‑pitch sound.

On the grid, draw a trace to represent the sound wave produced by the alarm.

A student uses an oscilloscope to determine the speed of sound.

The diagram shows the oscilloscope trace produced by the sound wave.

The student uses two microphones and a ruler to determine the wavelength of the sound wave.

He finds that the wavelength is 1.4 m.

State the formula linking the speed, frequency and wavelength of a wave.

Use the oscilloscope trace to calculate the speed of the wave.

Another student uses this method to determine the speed of sound.

Step 1 The student stands 50 m away from her teacher, measuring the distance with a metre ruler.

Step 2 The teacher makes a loud sound and flashes a light at the same time.

Step 3 The student starts the stopwatch when she sees the flash of light.

Step 4 She stops the stopwatch when she hears the loud sound.

The speed of sound is calculated using the formula

Evaluate whether this method could produce an accurate value for the speed of sound in air.

When a meteor explodes, light waves and sound waves are produced at the same time.

State the formula linking average speed, distance moved and time taken.

A person standing 1860 m away from the site of a meteor explosion hears the sound of the explosion 5.6 s later.

Calculate the speed of sound in air.

A scientist stands a long way from the meteor explosion.

Explain why he hears the explosion at a different time to when he sees it.

Sound is a longitudinal wave.

Describe what is meant by the term longitudinal wave.

In 2013, a meteor exploded above Russia.

Just before the meteor exploded, it was travelling at a speed of 19.2 km/s.

The mass of the meteor was estimated to be 1.25 × 10⁷kg.

State the formula linking kinetic energy, mass and speed.

Calculate the energy in the kinetic store of the meteor just before the meteor exploded.

A student investigates the speed of sound in air.

The student sets up two microphones, A and B, as shown in Diagram 1.

The microphones are connected to a datalogger.

A sound is made to the left of microphone A.

The datalogger records the time when the sound wave reaches each microphone.

The student uses the data to calculate the time taken for the sound wave to travel from microphone A to microphone B.

Describe how the student could determine the speed of sound in air using his calculated value of time taken.

Suggest why the student does not use a stop clock in this investigation.

The student investigates how the speed of sound in air varies with temperature.

He places several Bunsen burners in the space between the microphones, as shown in diagram 2.

He uses this method

• light all the Bunsen burners on a low heating flame

• measure the air temperature in three places between the microphones using three temperature sensors

• use the datalogger to record the time taken for a sound wave to travel from microphone A to microphone B

• determine the speed of sound

The student repeats this method as the air temperature increases.

Suggest why it is important for all the Bunsen burners to burn the same amount of gas each second.

The table shows the student’s results.

	Temperature in	C		Time	Speed
sensor 1	sensor 2	sensor 3	mean	in ms	in m/s
20.3	20.2	19.9	20.1	4.37	344
29.9	31.3	30.0	30.4	4.29	350
39.7	41.0	39.0	39.9	4.22	358
51.0	50.2	49.3	50.2	4.15	362
59.8	61.5	58.6		4.08	368

Calculate the mean temperature for the last row in the table.

Give your answer to a suitable number of decimal places.

The student plots his results and draws the line of best fit.

Draw a circle around the anomalous result.

370

State how the student should deal with the anomalous result.

Explain why a line graph is the correct type of graph to display these results.

Describe the relationship between the speed of sound in air and temperature.

A sonometer is a piece of equipment used to investigate the frequency of waves on a string.

The photograph shows a sonometer.

The string is under tension. When the string is plucked it vibrates to produce a sound wave.

Describe how an oscilloscope should be used to measure the frequency of the sound wave from the sonometer.

A student investigates how the frequency of sound from the sonometer varies with the length of the string.

This is the student’s method.

● apply a constant tension force to the string

● pluck the string and measure the frequency of the sound wave produced

● move the bridge to change the length of the string

● pluck the string and measure the new frequency of the sound wave produced

Repeat the method for different lengths of string.

Give a control variable for the student’s investigation.

The table shows the student’s results.

Calculate the mean frequency for a string length of 60 cm.

Plot a graph of the mean frequency and string length data on the grid.

Draw the curve of best fit.

Determine the string length needed to produce a sound wave of frequency 75 Hz.

The student cannot hear the sound from the sonometer for some of the string lengths tested.

Explain which of the string lengths produce sounds that humans cannot hear.

Diagram 1 shows two identical buzzers connected with springs.

Spring A is connected to a post.

A force acts on the apparatus for a short period of time, pulling both buzzers to the right.

During this time, buzzer A moves 2 cm and buzzer B moves 4 cm.

Explain why buzzer B travels with twice the average speed of buzzer A.

A student connects the microphone to an oscilloscope to measure the frequency of sound from the two buzzers while the force acts on the arrangement.

Explain the difference in the measured frequencies of sound from buzzer A compared to buzzer B.

Diagram 2 shows an oscilloscope trace.

The trace represents the sound wave received by the microphone from buzzer A.

Measure the period of the sound waves from buzzer A.

Give your answer in standard form.

Diagram 3 shows two distant galaxies and the Earth.

Light emitted from a nearby star has a wavelength of 590 nm.

The light from an identical star in galaxy P arrives at the Earth.

The wavelength of the light from the star in galaxy P is 600 nm.

Calculate the change in wavelength for light from the star in galaxy P.

Galaxy Q is twice as far away from the Earth as galaxy P.

Suggest how the speed of galaxy Q relates to the speed of galaxy P.

Suggest a value for the change in wavelength of light from an identical star in galaxy Q when the light arrives at the Earth.

Explain how comparing the speeds of the two galaxies provides evidence for the Big Bang theory.

This question is about sound waves.

Sound is an example of a type of wave.

State the name of this type of wave.

The speed of sound in liquids is greater than the speed of sound in gases.

Describe the arrangement of particles in liquids and in gases.

You may use diagrams to help your answer.

Suggest why the speed of sound in liquids is greater than the speed of sound in gases.

A buzzer is an electrical device that produces sound.

The frequency of sound produced by the buzzer is 1400 Hz.

State the formula linking speed, frequency and wavelength of a wave.

Sound travels at a speed of 340 m/s in air.

Calculate the wavelength of the sound wave from the buzzer.

Two students use this method to investigate sound from a moving source.

Student A connects a piece of string to the buzzer.

She spins round so that the buzzer moves in a horizontal circular path.

● she spins round at a slow speed

● she then spins round at a high speed

Student B stands several metres away from student A.

The sound heard by student A is different to the sound heard by student B.

Discuss the differences in the sounds heard by student A and student B.

This question is about sound waves.

Describe an experiment to measure the speed of sound in air.

You may draw a diagram to help your answer.

An oscilloscope can be used to determine the frequency of a sound wave.

The diagram shows an oscilloscope trace of a sound wave.

Calculate the period of this sound wave.

Calculate the frequency of this sound wave.