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60 Cards in this Set
- Front
- Back
most common radiation used for communications
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RADIO
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only portion of spectrum humans can see with the naked eye
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VISIBLE or OPTICAL
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two types of radiation used in medicine
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X-RAY and GAMMA RAY
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radiation perceived as heat
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INFRARED (IR)
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radiation that penetrates upper layers of human skin
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ULTRAVIOLET (UV)
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radiation with the longest wavelength
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RADIO
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radiation with the shortest wavelength
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GAMMA RAY
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radiation with the highest frequency
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GAMMA RAY
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radiation with the lowest frequency
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RADIO
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color with the highest frequency
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VIOLET
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color with the lowest frequency
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RED
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color with the longest wavelength
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RED
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color with the shortest wavelength
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VIOLET
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order of colors from low to high frequency
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ROYGBV
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order of radiation from long to short wavelength
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RADIO, MICROWAVE, IR, VISIBLE, UV, X-RAY, GAMMA RAY
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highest peak of a wave
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CREST
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lowest point on a wave
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TROUGH
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the height of a wave (from midline to crest or trough)
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AMPLITUDE
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how often a wave occurs
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FREQUENCY
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the distance from one point on a wave the the next repeating point
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WAVELENGTH
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as wavelength increases, frequency...
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DECREASES
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as wavelength increases, energy
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DECREASES
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as wavelength increases, speed
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STAYS THE SAME
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as wavelength increases, danger to life
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DECREASES
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As frequency increases, wavelength...
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DECREASES
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As frequency increases, energy...
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INCREASES
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As frequency increases, danger to life...
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INCREASES
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As frequency increases, speed...
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STAYS THE SAME (assuming in a vacuum)
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EM spectrum is a....
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Family of waves
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Do they need moving particles to transfer energy?
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No
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Can they travel in a vacuum?
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Yes
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What speed?
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Speed of light (3*10^8 ms^-1)
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Wave equation is:
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v = f . lambda
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Freq of visible light is from:
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380nm (Violet) to 740nm (red)
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Energy transferred is proportional to :
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Frequency. hence gamma rays are most powerful, radio waves weakest
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Gamma Rays: source
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Nuclear reactors Radioactive substances Space |
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Gamma Rays: detector
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Geiger-Muller tube and counter
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Gamma Rays: applications
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Medical diagnosis Sterilisation of medical instruments Scanning shipping containers |
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Gamma Rays: additional facts
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Highest energy of EM spectrum Can't penetrate earths atmosphere Cause Ionisation, which affects living tissue |
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X Rays: Typical sources
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Fast moving electrons colliding with metal X ray machines in hospitals |
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X Rays: Detectors
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Geiger Muller tube and counter Darken photographic paper X-ray image intensifiers |
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X Rays: applications
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Medical imaging Airport security Analysis of molecules - xray crystallography |
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X Rays: additional facts
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High energy Can't penetrate earth's atmosphere Cause Ionisation, which affects living tissue |
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UV radiation: sources
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Sun UV lamps |
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UV radiation: Detector
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Some materials glow ( fluoresce) UV photodiode |
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UV radiation: applications
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Produces Vitamin D in skin Treating skin conditions Disinfecting hospital equipment Use by dentists to harden composite fillings |
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UV radiation: additional facts
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Most UV radiation blocked by atmosphere Comes in UVA, UVB, UVC UVC most dangerous, but blocked by ozone layer Suntan, sunburn, skin cancer from UVA, UVB Causes ionisation |
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Visible Light: Source
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Sun Lightbulbs lasers |
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Visible Light: detectors
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Eyes Photodiodes Phototransistors |
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Visible Light: applications
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Communication through optical fibres Lasers - eg in supermarkets Medical uses of lasers |
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Infrared rays: sources
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Sun Infrared heaters |
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Infrared rays: Detectors
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Thermopiles Black bulb thermometers |
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Infrared rays: applications
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Heating Night vision Medical diagnosis and treatment Passive IR detectors in alarms |
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Infrared rays: additional facts
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IR rays are responsible for heat transfer by radiation Half the radiation received from the sun is IR Most radiation re-emitted by Earth is IR This regulates the planetary temperature |
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Microwaves: Sources
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Microwave ovens
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Microwaves: detectors
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Radar dishes
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Microwaves: applications
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Ovens Communications |
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Radio Waves: Sources
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Radio transmitters Space |
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Radio Waves: Detectors
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TV/radio aerials Radar dishes |
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Radio Waves: Applications
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Communication
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