Wave Behaviour (OCR GCSE Physics A (Gateway))

Look at the diagram of a water wave.

i) What is the wavelength of this wave?

Answer = .........................cm [1]

ii) What is the amplitude of this wave?

Answer = .........................cm [1]

iii) The wavelength of the wave is changed to 25cm. Two waves are produced each second.

Use the equation: Wave speed = Frequency × Wavelength

Calculate the speed of the wave.

Answer = .........................m/s [2]

Water waves are transverse and sound waves are longitudinal.

i) Describe how water particles move in a transverse water wave.

[1]

ii) Describe how air particles move in a longitudinal sound wave.

[1]

Look at the diagram of the electromagnetic spectrum.

i) Name a wave that has a longer wavelength than red light.

[1]

ii) Name a wave that has a higher frequency than violet light.

[1]

iii) State two uses of gamma-rays.

1 .......................................................................................

2 .......................................................................................

[2]

Some students try to measure the speed of sound, as shown in Fig. 24.1.

One student makes a loud sound by clapping her hands.

The sound of the clap reflects from the gym wall causing an echo.

Another student measures the time between hearing the clap and hearing the echo.

Fig. 24.1

They repeat the experiment three times and record their results in the table below.

i) The student did not pay attention when recording time 3.

Calculate the mean time taken for the sound of the clap to return, using suitable values from the table.

Mean time taken = ................................ s

ii) Calculate the speed of sound for the clap.

Use your answer to (a)(i) and the equation: distance travelled = speed × time

Give your answer to 3 significant figures.

Speed of sound = ................................ m/s

iii) Describe two ways to improve and develop their method.

1 .......................................................................................

2 .......................................................................................

Higher Tier Only

Ultrasound wave pulses are used by vets to scan inner tissues inside animals.

The ultrasound pulses partially reflect from different layers of tissue. These reflected wave pulses (echoes) are collected by the detector as shown in Fig. 24.2.

Fig. 24.2

In a scan using ultrasound pulses, three layers of tissue are detected, with each layer having a different thickness.

Describe and explain how the results from the detector can show:

•   that there are three layers

•   that each layer has a different thickness.

A teacher uses water waves in a ripple tank to demonstrate transverse waves.

She makes measurements of the water waves.

The frequency of the water waves is 0.5Hz.

i) Calculate the number of water waves produced in 5 seconds.

Answer = ......................... [1]

ii) The teacher increases the frequency of the water waves.

Describe what happens to the speed and the wavelength of the water waves.

[2]

iii) A student tries to describe water waves in the sea.

‘The water waves move up and down. The water particles move all the way across the surface of the sea. This means that water moves in the direction of the waves.’

Part of his explanation is incorrect.

Write an improved and correct description about water waves in the sea.

[2]

A student watches a ball game on the school field.

The student sees the ball being hit with a bat but he hears the sound a short time after. This is because the speed of light is much greater than the speed of sound.

Describe an experiment which measures the speed of sound in air.

In your answer describe the measurements, calculations and procedures needed to gather accurate and reliable results.

You may draw a diagram as part of your answer.

 Higher Tier Only

Look at the diagram of a human ear.

Sound wave disturbances, outside the ear, transfer energy to the small hairs (cilia) inside the cochlea.

The cochlea then sends nerve impulses along the auditory nerve to the brain.

Explain how sound wave disturbances in the air outside the ear transfer to the small hairs (cilia) inside the cochlea.

A crowd makes a Mexican wave.

A Mexican wave starts with people lifting and lowering their arms.

The Mexican wave continues by people, next to them, lifting and lowering their arms.

Why is a Mexican wave an example of a transverse wave?

In the classroom a teacher demonstrates waves using a rope. Look at the diagram of the wave.

i) The frequency of the wave is 2 Hz. What does this statement mean?

[2]

ii) How many seconds will it take for this wave to travel 12 m?

Show your working.

Answer = ......................... seconds [3]

Higher Tier Only

Ultrasound scans are used to produce images of tissues inside the body.

Ultrasound waves are emitted.

The waves reflect from layers of tissue inside the body.

Explain how the reflections are used to produce an image of the tissues.

Higher Tier Only

Ultrasound and X-rays are used to scan patients in hospitals. Complete the table to show a medical use, benefits and risk of using these waves to scan patients.

Fig. 20.1 is a graph of a wave.

Fig. 20.1

i) Use the graph in Fig. 20.1 to work out the time period of the wave.

Time period of the wave = ................................ s [1]

ii) Use the graph in Fig. 20.1 to work out the amplitude of the wave.

Amplitude = ................................ cm [1]

iii) The frequency of the wave in Fig. 20.1 is 0.5 Hz.

What is meant by the term frequency?

[1]

A water wave has a frequency of 0.25 Hz and a wavelength of 6.0 m.

Calculate the speed of the wave.

Speed of the wave = ................................ m/ s

Surface water waves can be modelled using a slinky spring.

A student holds one end of the spring on a table. The other end is fixed to a wall.

Fig. 20.2 shows the spring viewed from above the table.

Fig. 20.2

i) Draw two arrows on the diagram in Fig. 20.2 to show the movement of the student’s hand when he makes a transverse wave.

[1]

ii) Describe what happens to the transverse wave at the wall.

[1]

iii) In Fig. 20.3 the student stops moving his hand.

This is what the coils in the spring look like after a short time:

Fig. 20.3

This model of a water wave shows that the wave travels not the water.

Explain why.

[1]

Ultrasound waves can be used to create an image of part of the inside of a body.

Ultrasound waves have a higher frequency than ripples on the surface of water.

Describe another difference between ultrasound waves and ripples on the surface of water.

Explain your answer.

The graph in Fig. 19.1 shows how displacement of the ultrasound wave varies with distance.

Fig. 19.1

i) Use the graph in Fig. 19.1 to determine the wavelength of the ultrasound wave.

Wavelength = ....................................................... m [1]

ii) The speed of ultrasound waves in (b)(i) is 4500 m/s.

Calculate the frequency of the ultrasound wave in Fig. 19.1.

Use the equation: wave speed = frequency × wavelength

Give your answer in standard form and to 2 significant figures.

Frequency = ..................................................... Hz [4]

Doctors can use an ultrasound scan to measure the size of a person’s kidney.

Fig. 19.2

Complete the sentences using the words below.

Each word may be used once, more than once, or not at all.

The ultrasound scanner is made from a solid ceramic material.

As the wave enters the body, the speed ................................................. .

As the wave enters the body, the frequency ........................................... .

i) Explain what happens to the ultrasound wave when it reaches the kidney.

[2]

ii) Fig. 19.2 shows the thickness of the kidney, w. Explain how ultrasound waves are used to measure w.

[2]

Higher Tier Only

A doctor uses an ultrasound scan instead of X-rays to measure the kidneys.

Explain why.