Waves

Question 1

What do waves transfer

Answer 1

Energy and information NOT matter

Question 2

Two types of waves

Answer 2

Transverse and longitudinal

Question 3

What is a transverse wave

Answer 3

Oscillations are perpendicular to direction of energy transfer

Question 4

What is a longitudinal wave

Answer 4

Oscillations are parallel to direction of energy transfer

Question 5

Examples of transverse waves

Answer 5

Electromagnetic waves
Seismic s-waves

Question 6

Examples of longitudinal waves

Answer 6

Sound waves
Seismic p-waves

Question 7

Two parts of longitudinal waves

Answer 7

Compressions and rarefractions

Question 8

Two parts of transverse waves

Answer 8

Peaks and troughs

Question 9

Waves amplitude

Answer 9

Maximum displacement of a point on a wave from its undisturbed position

Question 10

Wavelength

Answer 10

Distance from point to point on a wave to the same position on the adjacent wave. Commonly peak to peak or trough to trough.

Question 11

Frequency of a wave

Answer 11

The number of waves that pass through a given point each second

Question 12

Unit of frequency

Answer 12

Hertz
Hz

Question 13

What is meant by frequency of 200Hz

Answer 13

200 waves pass a given point each second

Question 14

Wave speed

Answer 14

The speed at which energy is transferred through a medium

Question 15

What does a wave transfer

Answer 15

Energy

Question 16

What is wave velocity

Answer 16

(Measured metres per second)
Is equal to the product of the wavelength and the frequency of the wave.

Question 17

Wave speed equation

Answer 17

Wave speed (m/s) = frequency (Hz) x wavelength (m)

Question 18

What is meant by period of the wave

Answer 18

Length of time it takes for one full wave to pass through a point

Question 19

Word used to describe when a wave bounces off a surface

Answer 19

Reflection

Question 20

What is the ‘normal’ (in terms of reflection and refraction)

Answer 20

A vertical imaginary line which is perpendicular to the boundary

Question 21

What occurs when light is reflected off a boundary

Answer 21

Bounces off a smooth flat surface so that the angle of incidence is the same as the angle of reflection

Question 22

What is refraction

Answer 22

Change in speed of a wave as it reaches a boundary between two media usually resulting in a change in direction if it enters at an angle

Question 23

What occurs when light is refracted at a boundary

Answer 23

The light changes speed and direction in the new medium. If new medium is more dense the light will travel slower and bend towards the normal. If the new medium is less dense the light will travel faster and bend away from the normal

Question 24

When entering a DENSER material light waves…

Answer 24

Slow down
Bend towards normal

Question 25

When entering a LESS DENSE material light waves …

Answer 25

Speed up
Bend away from normal

Question 26

How can refraction be measured

Answer 26

Angle of incidence (i)
Angle of refraction (r)
Can be measured and compared
All angles are measured relative to the normal

Question 27

What are effects of absorption of different wavelengths of waves in different mediums

Answer 27

Some materials behave differently depending on wavelength

Question 28

How do sound waves travel through solid

Answer 28

The particles in solid vibrate and transfer kinetic energy through the material

Question 29

How does the human ear work

Answer 29

1. Outer ear collects sound which travels into the ear
2. Sound waves cause eardrum to vibrate at the same frequency
3. This is amplified by three ossicles
4. Causes the hair in the cochlea to vibrate
5. Cochlea converts the vibrations into electrical signals
6. Signals are passed to brain through auditory nerve
7. Brain converts the electrical signals into sound

Question 30

Frequency range of human hearing

Answer 30

20 Hz - 20kHz (20,000Hz)

(1kHz = 1000Hz)

Question 31

What is an ultrasound wave

Answer 31

A sound wave with a frequency greater than 20,000Hz

Question 32

What is sound of frequencies less than 20Hz called

Answer 32

Infrasound

Question 33

What natural even causes seismic waves to be produced
What types are produced

Answer 33

Earthquakes
Produce both p-waves and s-waves

Question 34

Are p-waves transverse or longitudinal

Answer 34

Longitudinal

Question 35

Are s-waves transverse or longitudinal

Answer 35

Transverse

Question 36

State a difference between the mediums p-waves and s-waves can travel through

Answer 36

P-waves travel through BOTH solid and liquid
S-waves ONLY travel through solid

Question 37

Significance of S-waves and P-waves

Answer 37

They provide evidence that the earths core is liquid as only p-waves produced by earthquakes can be detected on the other side of the globe

Question 38

What technique is used to detect objects in deep water and measure water depth

Answer 38

Echo sounding
High frequency sound waves are emitted, reflected and detected
Time difference between emission and detections, alongside wave speed, are used to calculate distances

Question 39

How does sonar work

Answer 39

When ultrasound waves are emitted they reflect off boundaries and their echoes are detected
The speed of the ultrasound is known and also the time it takes to detect the echoes
Equation, distance = speed x time is used to find the distance travelled
The distance travelled is halved to give the distance between emitter and boundary

Question 40

How does foetal scanning work

Answer 40

An ultrasound wave is sent into the patients body
It passes through the body and reflects off the organs and tissue
The devise then uses the reflected ultrasound waves to produce and image of the foetus
Ultrasound is safe and does not damage cells