waves

Question 1

what is displacement?

Answer 1

the distance that a certain point in the medium has moved from its rest position

Question 2

peak

Answer 2

the highest point above the rest position

trough is lowest

Question 3

amplitude

Answer 3

the maximum displacement of a point of a wave from its rest position

Question 4

wavelength

Answer 4

distance cocered by a fully cycle of the wave, usually from peak to peak or trough to trough

Question 5

frequency

Answer 5

the number of waves passing a point each second

Question 6

time period of a wave

Answer 6

1/frequency

Question 7

wave speed

Answer 7

frequency x lamda (wavelength)

Question 8

how does sound reach a persons ear drum?

Answer 8

the air is made up of many tiny particles. when sound is created, the air particles vibrate and collide with each ither, causing the vibrations to pass between air particles. the vibrating particles pass the sound through to a persons ear and vibrate the ear drum

Question 9

what is the general name for waves that require a medium to vibrate?

Answer 9

mechanixal

Question 10

what is the speed of sound in air and water?

Answer 10

330 m/s in air

1500 m/s in water

Question 11

what are longitudinal waves?

Answer 11

in lonqitudinal waves, the vibrations are parallel to the direction of wave travel

Question 12

what are some examples of longitudinal waves?

Answer 12

sound waves

ultrasound waves

seismic p-waves

Question 13

longotudinal waves show areas of ______ and _________

Answer 13

compression

rarefaction

Question 14

compressions

Answer 14

are regions of high pressure due to particles being close together

Question 15

rarefactions

Answer 15

are regions of low pressure due to particles being spread further apart

Question 16

what is a transverse wave?

Answer 16

the vibrations are perpendicular to the direction of wave travel

Question 17

examples of transverse waves

Answer 17

• electromagnetic waves

ripples on water

seismic s-waves

Question 18

what are electromagnetic waves

Answer 18

their vibrations or oscillations are changes in electrical and magnetic fields at right angles to the direction of wave travel

Question 19

all electromagnetic waves can:

Answer 19

transfer energy as radiation from the source of the waves to an absorber

can travel through a vaccum

Question 20

em spectrum from longest to shortest

Answer 20

radio, microsaves, infared, visible light, ultraviolet, xrays, gamma rays

Question 21

red light has ___________. violet light has ________

Answer 21

red light has the lowest frequencies of visible light

violet has the highest

Question 22

radio waves

Answer 22

do not cause damage when absorbed by the human body

used for communications
television
radio

Question 23

microwaves

Answer 23

high frequency microwaves are absorbed easily into the food. the internal energy of the molecules increases when they absorb microwaves, which xauses heating

Question 24

infared

Answer 24

used by electrical heaters, cookers for cooling food, infared cameras

Question 25

visible light

Answer 25

it is used in fibre optix communications

Question 26

ultraviolet

Answer 26

cannot be seen by humans

causes tans
causes skin cancer

Question 27

xrays

Answer 27

internal imaging

absorbed by dense structures like bones

Question 28

ionising radiation

Answer 28

xrays and gamma rays can add or remove electrons from molecules, producing electrically charged ions

• UV can cause premature aging and skin cancer
• x and gamma rayscan cause the mutation of genes (cancer)

Question 29

the law of reflection states that

Answer 29

angle of incidence = angle of reflection

they are measured between the light ray and the normal

Question 30

explain refraction

Answer 30

the density of a material affects the speed that a wave will be transmitted through it. in general, the denser the transparent material, the more slowly light travels through it

Question 31

if a wave slow down, it‘s ______

Answer 31

wavelength will decrease

Question 32

what happens to a light eay when it travels from water into air?

Answer 32

it bends away from the normal

Question 33

which term is used to refer to the scattering of light by a rough surface?

Answer 33

diffuse reflection

Question 34

which term is used to refer to regular reflection from a smooth surface in a single direction?

Answer 34

specular reflection

Question 35

sound waves

Answer 35

ok

Question 36

the speed of sound depends on the _____

Answer 36

medium through which it is travelling

Question 37

how does the mechanism of the ear detect sound

Answer 37

sound waves enter the ear canal and cause the eardrum to vibrate. three small bones transmit these vobrations to the cochlea. this produces electrical signals which pass through the auditory nerve to tje brain, where they are interpreted as sound

Question 38

what is sound above 20 000 Hz called?

Answer 38

ultrasound

Question 39

uses of ultrasound

Answer 39

breaking kidney stones
cleaning jewellery

vibrations shake apart the dirt or kidney stones, breaking them apart

Question 40

how does echo sounding work?

Answer 40

the time between a pulse of sound being transmitted and detected can be used to calculate the distance of the reflecting surface

Question 41

seismic waves can cause

Answer 41

tsunamis and earthquakes

Question 42

explain what happens to water waves as they pass into a deeper region

Answer 42

waves teavel faster in deeper water and more slowly in shallow water. they will soeed up so wavefronts move further apart