Sound waves

Figure 16 is a diagram of part of a water wave.

Use data from Figure 16 to determine the amplitude of the wave.

Use data from Figure 16 to determine the wavelength of the wave.

wavelength =_........

The water wave shown in Figure 16 is generated in a large tank.

A student observes the wave.

Describe how the student could determine the wave speed of the wave.

When an earthquake happens, waves are transmitted through the Earth. Figure 17 is a diagram of a part of the Earth’s crust.

Earth’s surface

An earthquake happens at point X, 20 km below the Earth’s surface.

An earthquake wave from X is detected at point L.

This earthquake wave is a transverse wave.

State one other example of a transverse wave.

A point in the crust is labelled R in Figure 17. There is a rock at point R.

Describe the effect that this earthquake wave has on the rock at R as the wave passes through the rock.

You may add to Figure 17 to help your answer.

*(c) A scientist investigates a sample of an unknown radioactive material.

The scientist finds that the sample does not emit beta radiation.

The scientist sets up the experiment shown in Figure 18 and uses different absorbers to investigate alpha and gamma radiation.

The results are shown in Figure 19.

The count rates are rounded to two significant figures.

The background radiation was 18 counts per minute (cpm).

Discuss whether the sample emits alpha or gamma radiation or both.

Your answer should refer to

• the data shown in Figure 19

• how the data gives evidence for particular radiations.

Figure 5 is a diagram of part of a water wave.

Use data from Figure 5 to determine the amplitude of the wave.

Use data from Figure 5 to determine the wavelength of the wave.

wavelength =_........

The water wave shown in Figure 5 is generated in a large tank.

A student observes the wave.

Describe how the student could determine the wave speed of the wave.

When an earthquake happens, waves are transmitted through the Earth. Figure 6 is a diagram of a part of the Earth’s crust.

Earth’s surface

An earthquake happens at point X, 20 km below the Earth’s surface.

An earthquake wave from X is detected at point L.

This earthquake wave is a transverse wave.

State one other example of a transverse wave.

A point in the crust is labelled R in Figure 6. There is a rock at point R.

Describe the effect that this earthquake wave has on the rock at R as the wave passes through the rock.

You may add to Figure 6 to help your answer.

The wave from X reaches L 3.8 seconds after it passes through R.

The speed of the wave is 4500 m / s.

Calculate the distance between X and R.

A sound wave can transfer information across a room.

Which row of the table shows what else a sound wave can transfer?

Which of these always increases as a sound gets louder?

The speed of a sound wave in air is 330 m/s.

The wavelength of this wave is 0.75 m.

Calculate the frequency of this wave.

Use the equation

Figure 10 shows a water wave.

Which of these is the amplitude of the wave shown in Figure 10?

Ripples travel out from the centre of a small circular pond to its edge.

Describe how a student could determine the wave speed of the ripples.

Figure 11 shows a duck floating on the pond.

The ripples cause the duck to move.

Draw arrows on Figure 11 to show how the duck moves due to the ripples.

Figure 9 shows two technicians, L and M, measuring the speed of sound in air.

L fires a starting pistol.

M starts a stopwatch when first seeing the smoke from the starting pistol.

M stops the stopwatch when hearing the bang made by the starting pistol.

The distance between L and M is 120 m.

M’s reaction time is 0.23 s.

The speed of sound in air is 330 m / s.

Calculate M’s reaction time as a percentage of the time sound takes to travel from L to M.

Which of these would improve the technicians’ measurement of the speed of sound?

Figure 10 shows the difference in refraction of sound waves and light waves when these waves travel from air into water.

Explain why the refraction of the sound wave is different from the refraction of the light wave in Figure 10.

Light is one example of an electromagnetic wave.

Light can transfer energy from a lamp to the leaf of a plant, causing chemical reactions in the leaf.

Describe examples of two other electromagnetic waves transferring energy.

This question is about waves.

Figure 3 is a diagram of a water wave in a ripple tank.

State the number of crests of the wave between P and Q.

The distance between P and Q is 42 cm.

Calculate the wavelength of the water wave in Figure 3.

wavelength =_........

Describe how a student could determine the wave speed of the water wave in Figure 3.

Which row of the table is correct for sound waves ?

A sound wave has a frequency of 440 Hz and a wavelength of 0.75 m.

Calculate the wave speed of the sound wave.

wave speed =_........

The human ear can only detect frequencies below ultrasound and above infrasound.

Which of these gives the approximate range of frequencies for the human ear?

Suggest two reasons why there are limits to the frequencies that a human ear can detect.

Ultrasound can be used to find cracks in metals.

Figure 13a shows the signals emitted and received when the metal bar has no cracks.

Figure 13b shows the signals emitted and received when the metal bar has a crack.

Explain how the signals in Figure 13a and Figure 13b show that there is a crack in the metal bar in Figure 13b.

Suggest one reason why the amplitude of signal R in Figure 13b is smaller than the amplitude of signal P shown in Figure 13a.

Figure 12 shows part of a wave.

Use data from Figure 12 to calculate the wavelength of the wave.

Figure 13 shows a student sitting on the shore of a lake watching ripples on the surface of the water moving past a toy boat.

The student has a stopwatch.

Describe how the student could determine the frequency of the ripples on the lake.

The speed of a water wave is 1.5 m/s.

The frequency of the wave is 0.70 Hz.

Calculate the wavelength of this wave.

Use the equation

v = f × λ

Water waves are transverse waves.

Describe the difference between transverse waves and longitudinal waves.

Sound waves travel at 330 m/s in air.

A student sees a flash of lightning.

The student hears the sound of thunder 4.0 s later.

Calculate the distance from the student to the flash of lightning.

Use the equation

x = v × t

This question is about ultrasound.

Which of these is a frequency of ultrasound?

Ultrasound has many uses.

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.

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.

Four students and their teacher do an experiment to measure the speed of sound in air.

The teacher stands at a distance and fires a starting pistol into the air. The students see the flash when the pistol is fired. They measure the time from when they see the flash to when they hear the bang.

A student drew a diagram of the arrangement as shown in Figure 7.

The students obtained a value of 240 m/s for the speed of sound.

The accepted value, in a science data book, is 343 m/s.

Calculate the difference between the students’ value and the accepted value as a percentage of the accepted value.

percentage difference =_........

When the distance was 100 m, the students measured the following times:

0.43 s 0.35 s 0.50 s 0.38 s

Explain why their times vary so much.

Explain one way the students might improve this experiment.

Figure 8 represents a sound wave coming from a loudspeaker and shows the effects on particles of the air at one instant in time.

Draw and label a distance of one wavelength in Figure 8.

Describe the motion of the particles as the wave travels through the air.

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

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

Explain one way the students could improve their method.

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.

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.

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

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

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.