Properties of waves

A student uses a ripple tank to investigate water waves.

Diagram 1 shows the ripple tank when viewed from the side.

A dipper moves up and down to produce waves on the surface of the water in the container.

The waves on the surface of the water are transverse.

State what is meant by a transverse wave.

You may draw a diagram to help your answer.

Diagram 2 shows the surface of the ripple tank, at an instant in time, when viewed from above.

Diagram 2

The dipper produces circular waves on the surface of the water.

1 cm in diagram 2 is equal to 2 cm in the laboratory.

Use the diagram to measure the wavelength of the water waves.

The dipper moves up and down with a frequency of 15 Hz.

Calculate the speed of the waves.

The student then makes the dipper move horizontally to the right at constant speed.

The dipper continues to move up and down with a frequency of 15 Hz.

Diagram 3 shows the surface of the ripple tank, at an instant in time, when viewed from above.

Diagram 3

Explain how the frequency of the waves arriving at point X compares with the frequency at which the dipper moves up and down.

A ball is moving through the air with a speed of 54.8 m / s. The ball has a mass of 159 g.

Calculate the energy in the kinetic store of the ball.

Give your answer to 3 significant figures.

The speed of the ball is measured using radio waves.

Radio waves of frequency 2.90 × 10¹⁰Hz travel towards the ball from a source.

The radio waves then reflect off the ball.

The reflected radio waves change frequency depending on the speed of the ball. This change in frequency is due to the Doppler effect.

The change in frequency can be calculated using this formula.

Show that the change in frequency of the radio waves is approximately 1.1 × 10⁴Hz.

[speed of radio waves = 3.00 × 10⁸m / s]

The change in frequency of the radio waves happens because the ball acts as a new source of radio waves.

The ball is moving away from the original source of radio waves.

Explain the change in frequency of the radio waves when the radio waves reflect off the ball.

This question is about cosmic microwave background radiation (CMBR) and the Big Bang.

CMBR has a mean frequency of 1.6 × 10¹¹Hz.

State the formula linking wave speed, frequency and wavelength.

Show that the mean wavelength of CMBR is about 2 mm.

[speed of light = 3.0 × 10⁸m/s]

CMBR was first released after the Big Bang.

When CMBR was first released it had a wavelength of about 9 × 10^–5mm, but now it has a wavelength of about 2 mm.

Using this information, explain how CMBR supports the Big Bang theory.

Explain how the cosmological red‑shift of galaxies also supports the Big Bang theory.

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?

The diagram shows two whales in the sea.

Some species of whale communicate with sound signals and visual signals.

Describe the difference between the motion of particles in a transverse wave and the motion of particles in a longitudinal wave.

You may use a diagram to help your answer.

Whale A makes a sound with a constant frequency. This sound is detected by whale B.

When whale A swims towards whale B, the frequency of the sound detected by whale B increases.

This is known as the Doppler effect.

Explain how the Doppler effect causes the frequency of sound detected by whale B to increase.

Visible light from the Sun reaches whale B.

The wavelength of this light is 5.410^–7m.

Calculate the frequency of this light.

[speed of light = 3.0×10⁸m/s]

Diagram 1 shows a Hertzsprung–Russell (HR) diagram.

Draw a cross to show the position of the Sun on the HR diagram.

In approximately 4 billion years, the Sun will enter the next stage of its evolution.

Draw a circle on the HR diagram around the area that will include the Sun in the next stage of its evolution.

Describe the stars that are in the top left corner of the HR diagram.

Diagram 2 shows how the brightness of two stars, star A and star B, changes with time.

These stars are called Cepheid variables.

Determine the period of the variation in brightness for these stars.

Calculate the frequency of the variation in brightness for these stars.

State what is meant by the term absolute magnitude.

Star A and star B have the same absolute magnitude but star A is always brighter than star B in the night sky.

Explain how this is possible.

The photograph shows infrared heating lamps being used to harden fresh paint on

Give a harmful effect of infrared waves.

The heating lamps produce visible light waves in addition to infrared waves.

Give two similar properties of visible light waves and infrared waves.

Give two differences between the properties of visible light waves and infrared waves.

The infrared heating lamps are placed 1.5 m from the car.

Calculate the time taken for infrared waves emitted from a lamp to reach the car.

[for infrared waves, speed = 3.0 × 10⁸m/s]

Paint takes less time to harden when it absorbs more energy from infrared radiation.

A technician observes that white paint takes more time to harden than black paint.

Explain this observation.

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.

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.

This question is about microwave ovens and microwaves.

A microwave oven cooks some food.

Diagram 1 represents a microwave emitted by the microwave oven.

Determine the wavelength of the microwave.

The microwave has a frequency of 2.35 GHz.

Show that the speed of the microwave is about 310⁸m/s.

Diagram 2 shows a damaged microwave oven with a hole in the door.

This microwave oven should not be used as it is very dangerous.

State a harmful effect from the microwaves if this oven is used.

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.

Ground-penetrating radar (GPR) uses radio waves to detect changes in material underground.

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

GPR radio waves have a frequency of 170 MHz.

The speed of radio waves is 3.0 × 10⁸m / s.

Calculate the wavelength of the waves.

A radio wave passes through the ground and refracts at the boundary between soil and rock.

The diagram shows three wavefronts of the wave before and after refraction.

The wave is also reflected at the boundary between the soil and the rock.

Complete the diagram to show three wavefronts after the wave has been reflected at the boundary.

Explain why the radio waves passing through the rock have a smaller wavelength than the radio waves passing through the soil.

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.

This question is about waves.

The diagram represents a wave.

Determine the amplitude of the wave by measuring it with a ruler.

Determine the wavelength of the wave by measuring it with a ruler.

Microwaves are part of the electromagnetic spectrum.

Name the part of the electromagnetic spectrum that has a lower frequency than microwaves.

Microwaves travel at a speed of 3.0 × 10⁸m / s in air.

A microwave has a wavelength of 2.7 cm.

Calculate the frequency of this microwave.

[wave speed = frequency × wavelength]

A student uses a microwave source and a receiver to investigate microwaves.

Photograph 1 shows how the student sets up their apparatus.

The meter shows the strength of the microwaves detected by the receiver.

The strength of the microwaves is measured in arbitrary units.

The student varies the distance between the microwave source and the receiver, and records the meter readings.

Photograph 2 shows the analogue meter for one of the readings.

Give the reading on the analogue meter.

reading =_........ arbitrary units

The graph shows the results of the student’s investigation.

The student concludes that the meter reading is inversely proportional to the distance between the microwave source and the receiver.

To be inversely proportional

meter reading × distance = constant

Comment on the student’s conclusion.

You should use data from the graph in your answer.

This is a question about electromagnetic waves.

State which colour in the visible spectrum has the shortest wavelength.

Explain a hazard of ultraviolet radiation to the human body.

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

Calculate the frequency of radio waves with a wavelength of 15 m.

[speed of light = 300 000 000 m/s]

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.

An ultrasonic distance-measuring device can be used to measure the length of a room.

The device emits a pulse of sound with a frequency of 40 kHz.

The device also emits a bright beam of red visible light.

Explain what is meant by a frequency of 40 kHz.

A sound wave from the device travels at 345 m / s.

State the formula linking wave speed, frequency and wavelength.

Calculate the wavelength of the sound wave.

The device emits a sound wave.

The sound wave travels to the wall, reflects back to the device and is received by the device.

The distance from the device to the wall is 2.35 m.

Calculate the time between the sound wave being emitted and received by the device.

Suggest why the device emits visible light.

Sound waves and light waves can have different frequencies and wavelengths.

Describe three other differences between sound waves and light waves.

You may draw diagrams to support your answer.

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.

X‑rays and gamma rays are examples of ionising radiation.

Which of these is another example of ionising radiation?

Give one use of x‑rays and one use of gamma rays.

x‑rays

gamma rays

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

Calculate the wavelength of a gamma ray with a frequency of 2.8 × 10¹⁹Hz.

[speed of gamma ray = 3.0 × 10⁸m/s]

X‑rays and gamma rays are electromagnetic waves.

Which of these graphs is correct for waves travelling at a constant speed?

Wi-Fi signals are electromagnetic waves that can be transmitted at frequencies of 2.4 GHz and 5.2 GHz.

State a similarity of the Wi-Fi signals at 2.4 GHz and 5.2 GHz.

The two Wi-Fi signals have different frequencies.

State another difference between the Wi-Fi signals.

State the formula linking speed, frequency and wavelength.

Calculate the wavelength of Wi-Fi signals transmitted at 5.2 × 10⁹Hz.

[speed of light = 3.0 × 10⁸m / s]

Which type of wave is a Wi-Fi signal?

Describe the difference between a transverse wave and a longitudinal wave. You may draw a diagram to help your answer.

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.

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 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.

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.

This question is about wave behaviour.

The boxes give three types of wave behaviour and the diagrams give three examples of wave behaviour.

Draw one straight line from each wave behaviour to the example that best shows that behaviour.

Wave behaviour
Example

State two properties that all waves have in common.

This question is about atmospheric optical illusions.

A mirage is an optical illusion formed due to total internal reflection of light from the sky at the boundary between cold air and hot air.

Diagram 1 shows how a mirage is formed.

State the formula linking critical angle and refractive index.

The critical angle of the cold air at the boundary is 88.500°

Calculate the refractive index of the cold air.

Give your answer to 5 significant figures.

Diagram 2 shows a ray of light from the Sun.

The refractive index of the atmosphere is greater than the refractive index of space.

Complete the diagram by drawing the path of the ray of light through the atmosphere.

Diagram 3 shows a ray of light from the Sun when the Sun is directly overhead.

Explain why the ray of light does not change direction when it enters the atmosphere.

Explain why the wavelength of the light reduces when it enters the atmosphere.

Suggest why the Sun appears not to be circular when it is close to the horizon at sunset.

This question is about a radio powered by a person turning a handle.

The radio has a battery which stores energy when the handle is turned.

The diagram shows the part of the radio called a generator.

The generator produces a voltage which does electrical work on the battery.

Explain how the generator produces a voltage.

The radio receives a radio wave of frequency 93 MHz.

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

Calculate the wavelength of the radio wave.

[speed of radio waves 3.0 × 10⁸ m/s]

The signal received by the radio is converted into an alternating current (a.c.) signal.

Describe how the loudspeaker in the radio converts this a.c. signal into a sound wave.

State a modification that would increase the force on the loudspeaker coil.

X-rays are electromagnetic waves used to obtain images of bones.

An x-ray machine produces x-ray waves with a frequency of 1.25 × 10¹⁸ Hz.

Calculate the time period of these x-rays.

X-rays have a speed of 3.00 10⁸ m/s in air.

Calculate the wavelength of these x-rays.

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.

A light ray travels from air into water.

Diagram 1 shows the direction of the light ray and the wavefronts in air.

Diagram 1

The refractive index of water is greater than the refractive index of air.

Complete diagram 1 by showing

● the wavefronts in the water

● the path of the light ray in the water

Explain what happens to the wavelength of light when it passes from air into water.

Diagram 2 shows what can happen when a light ray travelling in glass meets the boundary with air.

The wavefronts are not shown in this diagram.

Diagram 2

Add the normal to diagram 2.

Measure the angle of incidence in diagram 2.

angle of incidence =_........ degrees

The glass has a refractive index of 1.6

Calculate the critical angle of the glass-air boundary.

critical angle =_........ degrees

Explain the path of the light ray shown in diagram 2.

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.