electromagentic waves their uses and dangers

are electromagnetic waves transverse or longitudinal

transverse

they have a wide range of frequencies as

they are generated by changes in atom/nucleus

they transfer energy from source to

absorber

radio waves use and why it`s best

communication in tv or radio

radio waves can travel long distances before being absorbed

they can travel long distances as they either reflect off ionosphere or diffract(bend)

microwave use and why it`s best

heat up food- microwaves easily absorbed by water molecules in food transferring energy and rising temp

satellite communication-microwaves can pass through earth atmosphere without being reflected or refracted

infrared use and why it`s best

infrared heater, temp monitor- objects surfaces easily absorb infrared

visible light use and why it`s best

optical fibres- thin glass stands get transmitted light to create impulses and carry info eg tv signals

good as - short wavelength = more info carried

ultra violet use and why it`s best

energy efficient lamps- wave created in but has more energy than light

energy absorbed by internal surface of bulb

converted into light

good as- cheaper than normal bulb

gamma and x ray use

medical use broken bones detecting cancer

why are some waves like radio waves not dangerous

low frequency means it can pass soft tissue without causing damage

xray and gamma and uv sare dangerous as

uv-surface cell damage premature skin aging risk skin cancer

gamma and x ray-destroy cells mutate genes cause cancer

the unit radiation danger is measured in

sieverts -1000millisieverts=1 regular

how much damage radiation causes depends on

type of radiation and how much is absorbed