EM Waves in Depth Flashcards
electromagnetic wave
oscillating Electric and magnetic waves perpendicular to each other
speed of light
3 x 10-8
highest frequency
gamma rays
lowest frequency
radio waves
higher the frequency . . .
higher the energy, lower wavelength
microwave uses
cooking food - water molecules absorb energy, satellite communications
infrared uses
cooking food, cameras - emit red glow, heaters
visible light uses
vision, photography, fibre optics - no lost to sides
ultraviolet uses
energy efficient bulbs, fluorescent light - bulb coating absorbs, tan, security marking
x-ray uses
medical imaging, photographic plate uses for shadows
gamma rays uses
medical treatment, food sterilisation
dangers of EM
heating effect, change in nuclei - EM generates over wider range + electrons move, skin cancer, ageing, cancer - ionising
why are transmitters tall?
radio waves travel in straight lines
shorter wavelength . . .
more information over less range, less spread out
carrier wave
wave carrying any type of signal
dangers of microwaves
via phones, less dense younger skulls penetrate through affecting brain
how are x-rays produced?
particles moving at a high speed are stopped
contrast medium use + example
barium, see image more clearly as easy absorption
CCD
charge-coupled device, flat panel detector to convert x rays into visible light for image
why is a lead plate placed between a patient and tube?
x rays do not reach other parts of body
computerised technological x rays disadvantage
exposed to more radiation for longer amount of time
by gamma rays killing 99% of bacteria and their waste . . .
food shelf life is increased and food waste is decreased, spread of hospital disease is decreased
what emits gamma rays for cancer treatment?
cobalt-60
