P3 - Waves Flashcards
waves
definition of waves
transfers energy outwards from a source, through a medium, without the movement of matter and particles
definition of electromagnetic waves
consists of oscillating electric and magnetic field with no medium required. It travels fastest in a vacuum
definition of mechanical waves
transfer of energy through oscillation of particles (medium is required). It travels faster in a denser medium
definition of transverse waves
direction of vibration is perpendicular to the direction of energy transfer (propagation)
what does the type of wave depend on?
direction of oscillation
give 3 examples of transverse waves
-electromagnetic radiation
-water waves
-seismic secondary waves
definition of longitude waves
direction of vibration is parallel to the direction of energy transfer (propagation)
give 2 examples of longitudinal waves
-sound waves
-seismic primary waves
definition of wavelength
distance between trough/crest of wave and next trough/crest
what is the energy if the wavelength is low?
high
what should the x axis be for the wavelength to be
distance/displacement
definition of amplitude
how big the oscillation around the mean is
what are 3 things that happen when there is a high amplitude?
-more energy
-loudness increases
-water waves move more
definition of frequency
number of troughs that pass through a certain point each second
what happens to the energy when there is a higher frequency?
more energy
definition of time period
time taken to complete 1 cycle
what should the x axis be for time period to be?
time
what happens to the frequency and wavelength when a wave changes medium?
frequency stays the same
wavelength changes
where is the speed of light fastest?
in vacuum
where is sound fastest?
dense medium
why is it called electromagnetic waves?
wave consists of electro and magnetic fields
what is the speed of electromagnetic waves in a vacuum/air?
high speed - 3x10^8 m/s
state the electromagnetic spectrum from least to most energy
radio –> micro –> infrared –> visible –> ultra-violet –> x-ray –> gamma
radio waves have the highest/longest …?
wavelength
gamma rays have the highest …? and most …?
highest frequency
most energy
state 3 uses of radio waves
-radio
-television transmissions
-radar
state 3 uses of microwaves
-satellite television
-mobile phone
-microwave ovens
state 2 uses of infrared waves
-remote controllers for televisions
-thermal imaging
state 2 uses of visible waves
-vision
-photography
state 1 use of ultra violet waves
detecting fake bank notes
state 2 uses of x-ray waves
-medical scanning
-security scanners
state 2 uses of gamma ray waves
-detection of cancer
-cancer treatment
state 3 harmful effects of ultra-violet
-damage to surface cells and eyes
-can lead to skin cancer
-can lead to eye conditions
state 1 harmful effect of x-ray waves
mutation/damage to cells in the body
state 1 harmful effect of gamma ray waves
mutation/damage to cells in the body
cause of harmful effects on people (electromagnetic spectrum)
excessive exposure to electromagnetic radiation
what is sound produced by?
vibrating sources
what are longitudinal nature of sound waves in air?
series of compressions and rarefactions
definition of compressions
regions of higher pressure because particles are closer together
definition of rarefactions
regions of lower pressure because the particles are spread further apart
whats the range of frequencies audible to humans?
20Hz - 20kHz
what is needed to transmit sound waves
medium
sound travels fast in …,then …, then ….
solid, then liquid, then gas
what do the changes in amplitude and frequency affect?
loudness and pitch of sound waves
definition of echo
reflection of a sound wave
definition of ultrasound
sound with a frequency higher than 20kHz
