Waves Flashcards

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1
Q

what can waves transfer and what does it not

A

energy and information without transferring matter

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2
Q

what 5 pieces of data can be used to describe a wave

A

frequency
speed
wavelength
amplitude
period

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3
Q

what is wavelength

A

the distance from one crest of a wave to another

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4
Q

what is the amplitude

A

the distance from the top of a wave to the middle

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5
Q

what are the 2 types of waves

A

longitudinal
transverse

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6
Q

what are 2 examples of longitudinal waves

A

sound waves
seismic P waves

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7
Q

what is a longitudinal wave

A

where the particles move back and forth along the direction the sound is travelling

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8
Q

what are 2 examples of a transverse wave

A

EM waves
seismic S waves

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9
Q

what is a transverse waves

A

where the particles move at right angles to the direction the waves are travelling

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10
Q

what is the formula for the period

A

1/frequency

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11
Q

what are the 2 equations that can be used to find the speed of a wave

A

speed = distance/time
speed = frequency * wavelength

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12
Q

what are 2 ways to measure wave velocity in air

A

using an echo
using 2 microphones and an oscilloscope

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13
Q

what 2 tools are used to measure the speed of ripples on the water surface

A

ripple tank
strobe light

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14
Q

what 4 things can happen to a wave when it hit a boundary

A

reflected
refracted
absorbed
transmitted

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15
Q

when are sound waves transmitted

A

when the densities of the 2 materials are similar

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16
Q

when are sound waves absorbed

A

when the material absorbs sound waves

17
Q

when are sound waves reflected

A

big difference in densities

18
Q

why do sound waves get refracted

A

when they move between materials of different materials which causes different parts of the wave to slow down and change direction

19
Q

how are sound waves created

A

when an object vibrates

20
Q

what is the human hearing range

A

20Hz - 20’000Hz

21
Q

how does the ear work

A
  1. sound waves travel down the ear canal
  2. sound wave hits ear drum skin
  3. the compression and decompression of the air particles cause the eardrum to vibrate
  4. the vibrations are converted into electrical signals
22
Q

what are the 2 types of sound waves

A

ultrasound
infrasound

23
Q

what is ultrasound

A

sound waves with a frequency higher than 20’000Hz

24
Q

what is infrasound

A

waves with a frequency lower than 20Hz

25
Q

what are 2 uses of ultrasound

A
  • used to make images of the inside of the body such as scans of babies
  • used in sonar
26
Q

what are 2 uses of infrasound

A
  • track the path of meteors
  • determine rock structure beneath the earth’s crust
27
Q

how is ultrasound used in prenatal scans

A

the ultrasound is harmless and can be sent into the body. it will be reflected when it meets tissues with different densities. a scanner can detect the echoes and use it to create an image

28
Q

how is ultrasound used in sonar

A

uses of pulses of ultrasound that are sent towards the seabed. and equipment is used to measure the time between sending the sound and detecting its echoes so that the distance to the seabed and the depth can be calculated

29
Q

when are sound waves the fastest and why

A

in solids, the highest densities