waves Flashcards
what are the two types of wave
transvers and longitudinal
what makes a transverse wave
when the oscillation is perpendicular (90 degrees) to the flow of energy
what makes a longitudinal wave
when the oscillation is parallel to the flow of energy
give some examples of transvers waves
All electromagnetic waves (radio, microwave, IR, visible light, UV, X-rays and gamma) water waves, s-waves, Mexican waves
give some examples of longitudinal waves
sound, ultrasound and P-waves
what do the terms compression a rarefaction mean
compression is when a wave squashes the particles together (high pressure) rarefaction is when the particles are stretched apart by the wave (low pressure)
what does the term frequency mean and what is its unit
the number of waves or vibrations per second (measured in hertz)
what does the term wavelength mean and what is its unit
the distance between two successive peaks or trough of a wave (measured in meters)
how do we calculate wave speed
either time how long it take to travel a known distance and divide distance by time, or multiply its frequency by its wavelength
what does the term amplitude mean
the height of the wave from its middle
what is the order of the EM spectrum starting with the longest
Radio microwave IR visible light UV X-rays Gamma
which EM wave has the shortest wavelength
Gamma
which has the highest frequency
Gamma
what are the uses of radio waves
televisions, car radios
what are the uses of microwaves
satellite communications, cooking food, WiFi
what are the uses of IR
toasters, grills, night vision cameras, remote controls
what are the uses of visible light
fibre optic communication, TV, cameras
what are the uses of UV
sun tanning, security marker pens, bank notes
what are the uses of x -rays and gamma
medical imaging and radiotherapy
which EM waves are ionising
UV, X-rays and gamma
what does ionising mean
the radiation has enough energy to knock electrons out of the orbits around atoms
why is ionising radiation bad for humans
ionising radiation can cause cancer
why is UV dangerous for humans
it can cause skin cancer and damage the eye
what type of cancers is associates with X-rays
bone cancers
how does period and frequency relate to each other
frequency is 1 divided by the period (inverse) and likewise period is 1 divided by the frequency
