P2 0.0 / 5 ? PhysicsElectromagnetic SpectrumGCSEOCR Created by: Hattie BarnettCreated on: 06-05-17 14:28 What is the EM spectrum in order of frequency (high to low?) Radio, microwave, infrared, visible light, uv, X-ray, gamma 1 of 26 How high is energy in a high frequency wave? Very high 2 of 26 What is ionisation? When radiation has enough energy to remove an electron from a molecule or atom 3 of 26 Why is ionising radiation damaging? It can mutate our cells causing cancer or kill them directly 4 of 26 How can we protect ourselves from ionising radiation? Reduce time exposed, shield to absorb 5 of 26 What can happen to radiation after it is emitted for a source? Transmission, absorption or reflection 6 of 26 What is radiation intensity? How much energy hits a m squared of a surface per second 7 of 26 What affects intensity? How much energy per photon and how many photons 8 of 26 Why does intensity decrease with distance? It's spreads out or some is absorbed 9 of 26 How do you calculate the total intensity of radiation? number of photons x energy in each photon 10 of 26 Give three uses of microwave radiation... Microwave ovens, mobile phone signals and satellite communication 11 of 26 Why are microwaves good for satellite communication? They are not absorbed by the atmosphere 12 of 26 What are infrared and light radiation used for? Optic fibres (signal doesn't weaken and little is absorbed) 13 of 26 What are radio waves used for? TV and radio transmissions (not absorbed by atmosphere) 14 of 26 What is the greenhouse effect? Greenhouse gases in the atmosphere reradiate radiation back down to Earth, acting as an insulating layer 15 of 26 What else do greenhouse gases do with radiation? Absorb it, reradiate back to Earth or into space 16 of 26 How is ozone formed? A UV molecule splits up an O2 molecule. The separate O molecules then join other O2 molecules forming O3 (ozone) 17 of 26 Why is ozone important? When it is created it absorbs UV meaning it cannot harm us on Earth 18 of 26 What are 3 processes that return carbon to the atmosphere? Respiration, Combustion, Volcanic activity, Decay 19 of 26 What are two processes that take carbon from the atmosphere? Dissolving into oceans, photosynthesis 20 of 26 How does deforestation affect the carbon cycle? Less photosynthesis and more combustion= greater CO2 in atmosphere 21 of 26 What are three impacts of Global Warming? Rising sea levels, drought, extreme weather eg. Hurricanes 22 of 26 What happens to information before transmission? It is converted to electrical signals 23 of 26 What is the difference between an analogue and digital signal? Digital signals have only a take only a one of a discrete number of values, analogue can take any value of a range 24 of 26 What is noise? Interferences/ electrical disturbances picked up by signals in transmission 25 of 26 Why are digital signals better than analogue? Noise is more easily removed, send several at once and are easily processed by computers 26 of 26
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