waves

Question 1

what are waves?

Answer 1

something that transfers energy but not the matter itself

Question 2

what happens in transverse waves?

Answer 2

the vibrations are perpendicular to the direction of wave motion

Question 3

what can transverse waves do?

Answer 3

travel on the surface of a liquid,

THEY CANNOT TRAVEL THROUGH LIQUIDS

Question 4

what are two examples of transverse waves?

Answer 4

-electromagnetic waves
-ripples and waves in water

Question 5

what happens in longitudinal waves?

Answer 5

the vibrations are parallel to the direction of the wave motion

Question 6

what is an example of a longitudinal wave?

Answer 6

sound waves

Question 7

what is wavelength?

Answer 7

the distance between two equivalent points

Question 8

what is the unit for wavelength?

Answer 8

meters (m)

Question 9

what is the equilibrium?

Answer 9

the rest position of the wave (where it is flat)

Question 10

what is the amplitude?

Answer 10

the height of the wave

Question 11

what is wavespeed measured in?

Answer 11

m/s

Question 12

what is frequency measured in?

Answer 12

Hertz

Question 13

what is frequency?

Answer 13

the number of complete waves passing a point each second

Question 14

what is the time period of a wave?

Answer 14

the time taken for one complete wave to pass a point

Question 15

what is time period measured in?

Answer 15

seconds

Question 16

what does a ripple tank measure?

Answer 16

the speed of water waves

Question 17

what is frequency of the stroboscope equal to?

Answer 17

the frequency of water waves

Question 18

what happens when light enters dense materials like glass or water?

Answer 18

the light slows down- this causes it to change direction as it refracts towards the normal line as it slows down

Question 19

what are two examples of dense materials?

Answer 19

glass
water

Question 20

how could you improve the image of ripples when doing the ripple tank experiment?

Answer 20

-increase the light intensity of the lamp
-turn off the lights

Question 21

when a wave meets a boundary between two materials what two things can happen?

Answer 21

-the wave can refracted/transmitted
-the wave may be absorbed by the second material

Question 22

where is each angle measured from in the light and prisms pag?

Answer 22

the normal line

Question 23

what is refraction?

Answer 23

when waves bend

Question 24

what is the law of reflection?

Answer 24

that the incident angle is measured in the same place as the reflected angle

Question 25

the refracted angle is...

Answer 25

less than the incident angle

Question 26

what is refractive index?

Answer 26

a large refractive index means there is a greater difference in angle sizes (incident and refracted angles)

Question 27

why are incident and reflection angles not always equal?

Answer 27

-might be human error in using a protractor -getting a single narrow beam is tricky

Question 28

why does light bend away from the normal when it leaves the glass block?

Answer 28

-the light speeds up when leaving glass- therefore is bends away from the normal line, and therefore the angle of refraction is more than the angle of incidence

Question 29

what are electromagnetic waves?

Answer 29

light waves that are all around us (e.g radio, Xray)

Question 30

what is the difference between normal waves and electromagnetic waves?

Answer 30

em waves are a continous spectrum- the difference is the wavelength and frequency (there are no gaps)

Question 31

what do osciallating electrons produce?

Answer 31

radio waves- radion waves induce oscilation in the antena

Question 32

what kind of waves are electromagnetic waves?

Answer 32

transverse waves

Question 33

what are electromagnetic waves grouped based on?

Answer 33

wavelength and frequency

Question 34

what is the wave that we can see?

Answer 34

visible light

Question 35

what do different colours have?

Answer 35

different wavelengths: longest to shortest: Red, orange, yellow, green, blue, indigo, violet

Question 36

what is the order of the electromagentic spectrum?

Answer 36

longest wavelegth and low frequency to shortest wavelength and highest frequency: radio waves microwaves infrared radiation visible light ultra violet X-rays gamma rays

Question 37

the higher the frequency of the EM waves...

Answer 37

the more energy it transfers

Question 38

how are radio waves transmitted?

Answer 38

through the body without being absorbed

Question 39

how are infra red and visible light waves transmitted?

Answer 39

they are reflected or absorbed by the skin

Question 40

what can Infra red waves cause?

Answer 40

burns to the skin if too hot

Question 41

what is the downside to microwaves?

Answer 41

the waves can be absorbed which causes heating of the cells which may be dangerous

Question 42

what are the downsides to gamma rays and Xrays?

Answer 42

they can cause tissue damage and cancer. They have high frequencies aswell- causes even more damage

Question 43

what are radio waves used for?

Answer 43

communication and transmitting information e.g television and radio shows

Question 44

what are microwaves used for?

Answer 44

used for cooking and heating food, and communications to and from satelites

Question 45

what are infra-red waves used for?

Answer 45

-used for cameras which can detect IR radiation and detect people in the dark -electrical heaters -cookers for cooking food -short communications (e.g remotes)

Question 46

what are visible light waves used for?

Answer 46

-photography -illumination -also used in fibre optics for telephones and internet cables

Question 47

what are ultraviolet waves used for?

Answer 47

-energy efficient lamps -security pens- when exposed to UV light the ink will glow but invisible to others

Question 48

what are X-rays used for?

Answer 48

-viewing internal structures of objects and materials -used in hospitals to locate broken bones

Question 49

what are the negative aspects of X-rays?

Answer 49

they can cause cell damage

Question 50

what are gamma rays used for?

Answer 50

-used to sterilise medical equipment (they kill microbes) -used in radiotherapy

Question 51

what is infra red radiation emitted by?

Answer 51

humans or anything that has thermal energy

Question 52

why are alpha particles not as dangerous as beta or gamma?

Answer 52

alpha cannot penetrate into human cells beta and gamma can penetrate into human cells and ionise them

Question 53

what two waves are ionising?

Answer 53

x-rays and gamma rays

Question 54

which two waves can be used in communication?

Answer 54

radiowaves and microwaves

Question 55

what do waterwaves cause?

Answer 55

water waves cause particles to vibrate up and down

Question 56

what is a medium?

Answer 56

the material that the wave passes through

Question 57

where the particles are stretched far apart in longitudinal waves:

Answer 57

rarefractions

Question 58

what is a ripple tank?

Answer 58

a tray of water where a motor and rod that dip in and out of the water make ripples in the water

Question 59

how are ripples made it a ripple tank?

Answer 59

a motor and a rod that dips in and out make ripples in the water

Question 60

what is placed underneath the ripple tank?

Answer 60

a piece of paper to visibly see the waves in the water- the distance between each shadow on the paper is equal to the wavelength of the waves

Question 61

when an object absorbs infra-red radiation what happens?

Answer 61

it's temperature increases

Question 62

what is thermal imaging?

Answer 62

when humans or animals which emit infra-red radiation (heat) can be detected through infra-red cameras

Question 63

when waves travel through a vaccum they all have the same what?

Answer 63

velocity/speed they all travel at the same speed