P12- Wave Properties

Question 1

Wave

Answer 1

A wave is a means of transferring energy from one place to another without a transfer of matter between the two points.

Question 2

Types of waves

Answer 2

Mechanical waves, EM (Electronagnetic) waves

Question 3

Mechanical waves

Answer 3

Vibrations that travel through a medium

Question 4

Examples of mechanical waves

Answer 4

Sound waves, water waves, waves on springs and ropes, seismic waves

Question 5

Electromagnetic waves

Answer 5

Waves that can travel through a vacuum at the speed of 300,000,000 m/s. No medium is needed.

Question 6

Examples of EM waves

Answer 6

Light waves, radio waves and microwaves

Question 7

Transverse waves

Answer 7

The direction of oscillation is perpendicular to the direction of motion of the wave.

Question 8

What type of wave are all EM waves?

Answer 8

Transverse waves

Question 9

Longitudinal waves

Answer 9

The direction of oscillation is parallel to the direction of motion of the wave.

Question 10

What type of wave is a mechanical wave?

Answer 10

It can be transverse or Longitudinal

Question 11

Wave speed (ms^ -1) Equation

Answer 11

Frequency (Hz) x Wavelength (m)

Question 12

Amplitude

Answer 12

Distance from the rest position to the top of the wave.

Question 13

Frequency

Answer 13

The number of waves or oscillations per second (Hz).

Question 14

Time period

Answer 14

The tine for one wave to pass a given point or the time for one complete oscillation (s).

Question 15

Wavelength

Answer 15

Distance from one point on the wave to the identical point on the next wave.(m).

Question 16

Every second, 8 waves pass through the gap in the barrier. The waves have a wavelength
of 0.015 metres.
Calculate the speed of the water waves and give the unit.

Answer 16

8/1 = 8Hz
8 x 0.015 = 0.12m/s

Question 17

The Law of reflection

Answer 17

The reflected waves move away from the barrier at an equal angle to the incident waves.
Angle of incidence = angle of relection

Question 18

What can we use to investigate waves?

Answer 18

A ripple tank

Question 19

How does a ripple tank work?

Answer 19

Ripple tanks allow us to produce waves and observe how they behave when we introduce barriers, different gaps and change how deep the water is.

Question 20

Refraction

Answer 20

Refraction occurs when a wave changes direction as it changes speed when it passes from one medium to another. So the wavelength change as well but the frequency remain unchanged.

Question 21

What happens if a wave slows down?

Answer 21

It refracts toward the normal

Question 22

What happens if a wave speeds up?

Answer 22

If refracts away from the normal

Question 23

Transmission

Answer 23

The wave passes from the first material into the second material.

Question 24

Absorption

Answer 24

the energy of the wave will be transferred to the energy store of the second material.

Question 25

The audible range for human hearing is between ...

Answer 25

20 Hz and 20,000 Hz

Question 26

What frequency are ultrasound waves?

Answer 26

Over 20,000 Hz

Question 27

What is an ultrasound scanner?

Answer 27

It is an electronic device which makes use of a ‘transducer’ which can be placed on a surface through which it can sendpulses of ultrasound waves which can then also be detected – the results can then be shown on a display screen.

Question 28

Why can't X rays be used for baby scans?

Answer 28

Because they pass through organ tissue and because they are ionising(potentially harmful).

Question 29

Equation for finding distance with sound

Answer 29

Distance (m) = 1/2 x speed of ultrasound wave (m/s) x time (s)

Question 30

What is the problem with X-rays passing through organ tissue?

Answer 30

Unable to see defects in organ tissue

Question 31

What is an echo?

Answer 31

The reflection of a soundwave from a surface

Question 32

What is the study of Earthquakes called?

Answer 32

Seismology

Question 33

What are P-Waves?

Answer 33

The P stands for primary. These are push pull waves which are longitudinal.

Question 34

Key features of P-Waves?

Answer 34

● They can travel through liquid and solid so they can travel through the earth’s core. ● They travel fast. ● They are bent by the changing density of the rock. ● They are bent sharply when the material changes suddenly.

Question 35

What are S- Waves?

Answer 35

S stands for secondary waves. They are side to side waves (transverse).

Question 36

Key features of S-Waves

Answer 36

● They can only travel through solids. ● They are slower than P-waves. ● They are bent by the changing density of the rock. ● They are bent sharply when the material changes suddenly.

Question 37

What are L waves?

Answer 37

L-waves (Long waves), arrive last and cause violent movements on the surface up and down as well as backwards and forwards. They travel more slowly than P-waves or S-waves, and they only happen in the Earth’s crust.