Flashcards
P1.5 - EM Waves
Flashcards do conjunto (9)
- 1what is the em spectrum?radio waves, micro waves, infrared radiation, visible light, ultra violet, x rays, gamma rays
- 2describe radio waves*longest wavelength
*ones used for tv and radio cant travel long distances
*used for communication
*long wave have to diffract to travel long distances
*medium wave and short wave reflect off ionsphere to travel long distances - 3describe micro waves*used for satellite communication and mobiles
*travels as microwaves to satellite in space which transmits signal back
*microwave ovens use a different sized microwave - microwaves absorbed by water in food which heats up and heat is conducted and convected to rest of food
*health risks that microwaves absorbed by water in body and then kill cells but no evidence to prove - 4describe infrared radiation*can detect heat loss in house by infrared sensors as infrared is heat
*used in security systems to detect body heat
*used in night vision to turn heat into electrical signals
*used in cooking - toasters
*to transmit phone and computer information short distances
*carried as pulses in phone lines and reflected off sides of narrow core
*optical fibres
*remote controls as emit different patterns to send different commands - 5describe visible light*used in photos
*uses lens to focus visible light
*aperture controls how much light
*shutter speed controls how long exposed to light - 6describe ultra violet*from sun
*sun creams protect against
*tanning places have time limits for protection
*pale skin less protected
*can cause skin cancer
*causes sunburn - 7describe xrays*lead aprons and screens protect radiographers
*can cause cancer
*used in hospitals
*pass through flesh not denser bones
*used in airports to detect suspicious objects - 8describe gamma rays*shortest wavelength
*high doses can kill cancer
*can diagnose cancer
*radioactive isotope injected, gamma camera detect where travels and can then be used to create image to see possible cancer - 9describe ionization*forms an ion
*when radiation hits an atom sometimes energy displaces electron and ion formed
*high doses can kill cells
*longer exposed more damage
*can cause dna mutations and cells to divide - cancer
*only high energy em waves can cause ionization - UV and up (xrays and gamma)
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- Descrição
- GCSE Physics FlashCards sobre P1.5 - EM Waves, criado por scottjowett em 11-06-2015.
- Criado por
- scottjowett · jun 2015
- Atualizado
- 19 fev 2016
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