Flashcards
Physics -E-F
Cards in this deck (20)
- 1What are the best emitters and absorbersDull and black
- 2What are the worst emitters and absorbers(and so best relectirs)Shiny and White
- 3What signals do mobile phones useMicrowave
- 4Properties of infrared radiationHeats the surface of the food and is reflected by shiny surfaces
- 5What is infrared only absorbed byParticles in the surface of food increasing their energy
- 6What happens to the energy after it the particles have been heated up from infrared on the surfaceIt is transferred to the rest of the food by conduction and convection
- 7What are properties of microwave radiation- they penetrate (about 1cm) into food
-are reflected by shiny metal surfaces
- can cause burns when absorbed by body tissue
-pass through glass and plastics - 8What do water and fat absorbMicrowaves
- 9What are microwaves only absorbed byWater and fat in the outer layers of food increasing their kinetic energy
- 10What happens when microwaves transmit informationThere is some signal loss due to interference
-the curvature of the earth
-no diffraction around objects
- adverse weathe - 11What is the evidence of dangers from mobile phonesNot conclusive
- 12What decisions doesn't make it easy because the danger of mobile phones are not conclusiveThe siting of phone masts are a hard decision
- 13What happens as you increase the frequency of a microwaveThe energy increases
- 14What do analogue signals haveVariable value
- 15What are digital signals eitherOn(1) off(0)
- 16Everyday uses of infrared radiation remoteRemote controls and short distance data links
- 17What do infraredd sensors detectBody heat
- 18Advantages of using digital signalsEasier to remove noise and you can use multi plexing
- 19MultiplexingWhen you send one or more signal on a carrier wave
- 20The advantages of using optical fibresMultiplexing and lack of interference in the final signal
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- Flashcards on Physics -E-F, created by Emer Neave on 10/12/2014.
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- Emer Neave
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