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Physics > P5 - Waves > Flashcards

P5 - Waves Flashcards

1
Q

1 what is a wave

A

a transfer of energy not matter

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2
Q

1 how is energy carried

A

by the medium that oscillates or vibrates

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3
Q

1 what movement is

oscillation

wave direction

object movement

A

up down

left right

up down

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4
Q

1 what are the two types of wave

A

transverse
longitudinal

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5
Q

1 what is a transverse wave type

A

rope
water
light

oscillation is at 90* to the wave direction

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6
Q

1 what is longitudinal wave type

A

slinky springs
sand

oscillation is parallel to the wave direction

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7
Q

1 how do you measure waves

A

frequency
amplitude
frequency
time period

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8
Q

1 what is frequency

what is time period

A

waves passing a point per second

time for one wave in seconds

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9
Q

1 what is wavelength

what is amplitude

A

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

distance from an undisturbed position to biggest displacement

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10
Q

1 what is wavelength measured in

what does 25 hertz mean

A

metres

the frequency is 25 waves per second

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11
Q

2 what does the wave equation link

A

links speed and wavelength and frequency

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12
Q

2 what is the wave equation

A

wave velocity = wave length x frequency

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13
Q

2 what is wave velocity measured in

wave length?

frequency

A

metres per second

metres

hertz

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14
Q

2 what’s the equation for time period for one wave

A

Time = 1 / f

frequency= 1/t

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15
Q

2 how do you study waves at a beach

A

take a picture of the scene and estimate wave length

count waves pass in by in 1 minute
frequency = waves/ 60 seconds

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16
Q

2 how do you measure in a ripple tank

A

take an image
measure the wave length/ take the average

place a marker
press playback in slowmo
find the wave length frequency and amplitude

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17
Q

2 how do you measure with oscilloscope and sound

A

two microphones a measured distance apart

find the difference between the two patterns on the screen

sound of speed = distance / time

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18
Q

3 how do you measure wave speed

A

wavelength x frequency

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19
Q

3 what is wavelength if

30 cm has 8 waves

A

30/8 = 3.75cm

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20
Q

3 what is frequency if waves in 2 seconds = 25

A

25/2= 12.5 Hz

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21
Q

3 what’s the independent, dependent, and control variable of

determining wind speed pag

A

independent- frequency
dependent- wave speed
control- amount of water in tray, ripple tank design, distance from lamp to tank

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22
Q

3 how do you do the ripple tank experiment

A

place a ruler in the ripple tank
measure distance between wave peaks, wavelength
count how many waves pass a point at 10 seconds this is frequency
calculate wave speed
repeat for different frequencies

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23
Q

4 what are the 7 waves on the electro magnetic spectrum

A

gamma
x-ray
ultra violet
visible
infrared
microwave
radio wave

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24
Q

4 what frequency is gamma

what frequency is radio

A

high frequency
high energy short wave length

low frequency
low energy low wave length

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25
Q

4 what do visible waves show

A

colour

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26
Q

4 facts about electromagnetic waves

A

transverse
transfer energy
oscillations in electric and magnetic fields
can travel through space
speed of light is 300,000,000 m/s = wavelength x frequency
can reflect, retract, diffract

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27
Q

4 dangers and uses of gamma rays?

A

use
-in medicine, radiotherapy, sterilization, disinfection, nuclear industry

dangers
-causes ionisation that damages tissue and DNA
-could cause cancers

28
Q

4 dangers and uses of x rays?

A

uses
-examine most areas of body, soft-tissue and organs

dangers
-damage molecular structure and cause harm, risk of radiation

29
Q

4 dangers and uses of ultraviolet rays

A

uses
-killing bacteria, fluorescent effects, curing ink and resin, phototherapy and suntanning

dangers
-suppress proper functioning of body’s immune system and skins natural defence

30
Q

4 dangers and uses of visible rays

A

uses
-to see, screens, laser, photosynthesis, lighting and cameras

dangers
-blindness and burns

31
Q

4 dangers and uses of infrared rays

A

uses
-amplifying low light to enable video recording and photos, thermography to determine temperature

danger
-skin irritation, eye damage, increased risk of cancer, breathing and heart rate problems

32
Q

4 dangers and uses of microwaves

A

uses
-detect speeding acts, send telecommunication, dry and cure wood, cook food

dangers
-may cause infertility or cancer (very unlikely though)

33
Q

4 dangers and uses of radio waves

A

uses
-communications, transmissions, radio tomography

dangers
-raise body temperatures, burns, cataract formation, cause cancers, infertility

34
Q

5 when EM waves transfer energy, higher frequency means?

A

more energy

35
Q

5 which waves are ionising?

non-ionising?

A

ionising
-gamma
-x-rays
-UV

non-ionising
-visible
-IR
-Microwave
-radio wave

36
Q

5 pros and cons of ultra violet?

A

pros
-tanning
-skin products
-vitamin D

cons
-sunburn
-ages the skin
-skin cancers

ATOMSPHERE protects us from most UV

37
Q

5 what is ionisation?

A

an EM wave gives it energy to an electron that flies off
leaves an ion that is really reactive

38
Q

5 what does ionisation do to cells?

A

damages or repairs
cell dies
DNA damages so mutations form or cancers

39
Q

5 what do x-rays do

A

medicinal pictures
-bone absorbs flesh transfers
security at borders
-luggage
-people
-trucks

40
Q

5 what do gamma rays do

A

radiotherapy
-target cancers
-damages healthy tissues (radiation sickness)
sterilisation
-medical equipment
-food to make it last longer (NOT UK)

41
Q

6 what is low frequency and long wave length for?

A

end of the EM spectrum
useful for communication and for other devices because of its low energy

42
Q

6 what is a photon

A

a packet of energy

43
Q

6 what do visible rays do?

A

energy absorbed can start a chemical reaction - photosynthesis
chemical reactions happen in cells in our eyes
high intensity - heating effect (lasers)
optic fibres use pulses of light - 1001101000111010

44
Q

6 what do infrared rays do?

A

atoms on the surface absorb Infrared and warm up
also grills, toasters, hobs etc
infrared cameras can see heat
night vision
check insulation in homes
infrared remote controls can send signals over short ranges
11001001001110

45
Q

6 what do microwaves do?

A

water molecules absorb energy of some frequencies of microwaves and get hot
reflected by metals
uses by phones and masts as communication over a medium range (wifi too)

46
Q

6 what do radio waves do?

A

absorbed by electrons in aerial
long range communication(TV and radio)
analog changes the wave shape to convey into
digital uses 1 off pulses

47
Q

6 what is diffraction

A

occurs when wave is similar size to the gap

48
Q

6 what is reflection?

A

waves reflect off the appropriate medium and their energy transfers in a different direction

49
Q

6 when does refraction occur

how do you study it?

A

when a wave passes into a different medium

with ray boxes and a clear plastic box

50
Q

6 when also does refraction occur?

A

as the wave slows down entering the plastic, as its more dense, making it change direction

51
Q

7 what type of energy transfer is sound waves

A

energy -> kinetic energy

longitudinal
need a minimum
faster in liquids or solids as the particles are closer together

52
Q

7 what is the range of human hearing

A

20Hz - 20,000 Hz

53
Q

7 what type of vibrations is beating a drum

speed of sound in air?

A

parallel

300m/s

54
Q

7 what are oscillopes

A

allow us to study sound waves
more correctly the electrical signal going into the speaker

55
Q

7 wave shape when…

quiet (small amplitude) but high pitch (high frequency)
loud (large amplitude) but low pitch (low frequency)

A

not many waves but very big

lots of waves but very small

56
Q

7 wave shape when…

loud (large amplitude) but high pitch (high frequency)

quiet (small amplitude) but low pitch (low frequency)

A

lots of waves and very big

not many waves and very small

57
Q

7 whats an echo

A

when sound travels there and back

58
Q

7 if the speed is 1000m/s and it takes 4 seconds what is the depth of an ocean when using sonar technology to measure it?

A

4 x 1000 = 4000m
= 2000m depth

59
Q

7 how do ultrasounds work

A

collect return echoes from the inner surfaces to build up an image

60
Q

7 pros of ultrasounds and cons

A

pros
-real time
-cheap machine
-safe

cons
-images are a slice

61
Q

7 what axis is time on

what axis is voltage on

A

time = x axis

voltage = y axis

62
Q

8 what happens when you hear sound

A

when sound is absorbed the particles in the inner wall vibrate
wall gets hotter
the diaphragm of the microphone moves
when a mic absorbs the sound wave it produces a changing electric signal

63
Q

8 how do you hear

A

the outer ear (pinna and auditory canal) gather sound waves and direct to the ear drum
ear drum vibrates
the ossicles vibrate
act as small levers to amplify the vibration
pass it to the inner ear through the oval window
cochlea (like a shell) has fluid that transmits the oval window movement to small hairs
hairs attach to sound detection cell
sends a nerve to brain via auditory canal
brain processes and your hear

64
Q

8 why do you only hear particular frequencies

A

natural frequency (vibration depends on the length of ruler on the table etc)
cochlea hairs have natural frequency
if you apply vibration at natural frequency they will have a very big amplitude - resonance
hairs inside cochlea have different lengths and resonate at different frequencies
how your ear puts together different frequencies
range of frequencies depend on range of hair lengths

65
Q

8 why do you hear less when your older

A

you lose the short hairs in your cochlea, meaning its more difficult to hear higher frequencies

66
Q

8 what is resonance

A

objects that vibrate, like hairs in your cochlea have natural frequency
if you apply a vibration at natural frequency, they will vibrate with a very big amplitude

Physics (6 decks)

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