Topic 4 - Waves

Question 1

transverse waves

Answer 1

the mediums particles vibrate energy in a right angle to the direction of motion

Question 2

longitudinal wave

Answer 2

the mediums particles vibrate energy in the same direction of the motion

Question 3

mechanical waves

Answer 3

transfer of energy through a medium

Question 4

electromagnetic waves - type of wave

Answer 4

transverse waves that do not need a medium through which to travel

Question 5

wave frequency (Hz)

Answer 5

the number of waves passing a point each second

Question 6

period

Answer 6

the length of time it takes one wave to pass a given point

Question 7

wavelength of a wave (m)

Answer 7

the distance from a point on one wave to point in the same position on the next wave

Question 8

amplitude of a wave (m)

Answer 8

from the middle of the wave to the top or bottom

Question 9

velocity of a wave

Answer 9

the speed of the wave in the direction it is travelling

Question 10

velocity of a wave equation

Answer 10

velocity = frequency x wavelength

Question 11

wavespeed equation

Answer 11

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

Question 12

what can change the speed of a wave

Answer 12

the medium through which is it travelling

Question 13

refraction

Answer 13

when a wave travel from one medium through to another medium at an angle causing it to bend; this is caused by the wave changing speed as it passes through different mediums

Question 14

what’s happening to the speed of a wave if it bends towards the normal line

Answer 14

it’s slowing down

Question 15

what’s happening to the speed of a wave if it bends away from the normal line

Answer 15

it speeds up

Question 16

what controls how much light is bent

Answer 16

the greater the difference in speed between the two media’s
—> great difference = more light bent

Question 17

the normal line

Answer 17

the line that’s at a right angle to the interface

Question 18

the interface

Answer 18

the boundary between two media

Question 19

wave can be reflected

Answer 19

wave ‘bounces’ off the boundary

Question 20

waves can be refracted

Answer 20

the wave passes into the new material, but changes the direction in which is travelling (wave bends at the boundary)

Question 21

waves can be transmitted

Answer 21

the wave passes through the material and is not absorb or reflected

Question 22

waves can be absorbed

Answer 22

the wave disappears as the energy is carrying is transferred to the material (the wave is dispersed at the boundary)

Question 23

white light

Answer 23

made up of a mixture of different frequencies - we see these different frequencies as different colours

Question 24

why do we hear different pitches of sounds

Answer 24

because of different frequencies of sound

Question 25

what changes when a sound enters a different material

Answer 25

the wavelength and the velocity, NOT the frequency

Question 26

what type of waves are sound waves

Answer 26

longitudinal

Question 27

process to hear sound

Answer 27

1) sound waves enter the air canal 2) the eardrum is a thin membrane; sound waves make it vibrate 3) vibrations are passed on to tiny bones which amplify the vibrations (make them bigger) 4) vibrations are passed onto the liquid inside the cochlea 5) tiny inside the cochlea detect these vibrations and create electrical signals called impulses 6) impulses travel along neurons in the auditory nerve to the brain

Question 28

when a wave hits a boundary, what can it do

Answer 28

- be reflected - be refracted - be transmitted - be absorbed

Question 29

ultrasound

Answer 29

waves with frequencies too high to be heard by humans (above 20kHz)

Question 30

how can ultrasounds be used

Answer 30

- animals to communicate or navigate - sonar equipment to find the depth of the sea or detect fish - ultrasound scan to make images inside the body

Question 31

how does an ultrasound scan work

Answer 31

The ultrasound machine detect the time between sending the pulse out and receiving the echo

Question 32

infrasound

Answer 32

waves with frequencies too low to be heard by humans (below 20kHz)

Question 33

seismic waves

Answer 33

infrasound waves that are produced by earthquakes

Question 34

how are seismic waves detected

Answer 34

seismometer

Question 35

what types of seismic waves are there

Answer 35

longitudinal P waves or transverse S waves

Question 36

what type of waves are P waves

Answer 36

longitudinal

Question 37

what type of waves are S waves

Answer 37

transverse

Question 38

what type of states of matter can longitudinal waves transmit through

Answer 38

solids, liquids, gases

Question 39

what type of states of matter can transverse waves transmit through

Answer 39

only solids

Question 40

S wave shadow zone

Answer 40

the zone of the Earth on the opposite side to the earthquake

Question 41

why does the S wave shadow zone occur

Answer 41

because part of the earths interior is liquid so the waves can’t pass through it so underneath this liquid core, it’s a shadow zone

Question 42

for light what does the frequency determine?

Answer 42

colour - higher frequencies means blue colours - lower frequencies means red colours

Question 43

The sound what does frequency determine?

Answer 43

pitch - a high frequency results in a high pitch - a low frequency results in a low pitch

Question 44

What happens with light when amplitude changes

Answer 44

- Higher amplitude results in an increase of light - Low amplitude results in a decrease of light

Question 45

how do we work out the speed of waves on water?

Answer 45

Measure the time it takes for a wave to travel between two fixed points

Question 46

How do you work up the speed of sound?

Answer 46

Measure the time it takes for a sound to travel a certain distance, for example, measure the time it takes for an echo of a loud sound to reach you

Question 47

what happens when waves on the surface of water when they cross an interface from shallow water into deep water?

Answer 47

- They speed up

Question 48

what happens when waves on the surface of water when they cross an interface from deep water into water water?

Answer 48

- they slow down

Question 49

what happens when waves on the surface of water when they cross an interface from deep water into water water?

Answer 49

- they slow down

Question 50

explain the process of how the internal structure of a human air lets the brain hear sound

Answer 50

1. Sound waves enter the ear canal. 2. The eardrum is a thin membrane sound waves make it vibrate. 3. Vibrations apart from a tiny bones which amplify the vibrations (make them bigger) 4. Vibrations are passed onto the liquid inside the cochlear. 5. Tiny hairs inside the cochlear detect these vibrations and create electrical signals called impulses. 6. Impulses travel along neurons in the auditory nerve to reach the brain.

Question 51

what part of the cochlear detects high frequencies?

Answer 51

base

Question 52

Which part of the cochlea detects low frequencies?

Answer 52

apex

Question 53

Function of the hair cells in a cochlear

Answer 53

Detects vibrations - each cell is connected to a neurone that sends impulses to the brain

Question 54

function of the fluid inside a cochlea

Answer 54

fluid transmit sound waves