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25 Cards in this Set
- Front
- Back
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Waves |
Transfer energy from one place to another without transferring matter. Produced as a result of vibration. Two types: longitudinal and transverse. |
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Longitudinal wave
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Particles will move parallel to the direction of the wave.
E.g. sound waves and slinky spring waves. |
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Transverse wave |
Particles will vibrate at 90 degrees (perpendicular) to the direction of the wave.
E.g. oceanic waves, rope waves and electromagnetic waves. |
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Crest |
The top of a transverse wave |
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Trough |
The bottom of a transverse wave |
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Amplitude
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Longitudinal: the distance from the middle of a compression to the middle of a rarefaction or vice versa. Transverse: the distance from the undisturbed line to the crest or trough
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Wavelength |
Longitudinal: the distance from the middle of a compression to the next compression or from the middle of a rarefaction to the next rarefaction. Transverse: the distance from crest to crest or trough to trough. |
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Frequency |
Nr. of complete waves passing a certain point within a second.
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Wave speed |
wave speed = frequency x wavelength (λ)
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Electromagnetic waves |
Radio and microwaves Infrared Visible light Ultraviolet X-rays Gamma rays |
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Radio and microwaves |
Mobile phone and satellite transmissions
Microwave ovens - absorbed by water molecules Navigation (radar waves) Longest wavelength, less energy |
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Infrared radiation |
Given out by all hot objects Absorbed by objects, causing their temp. to rise - toasters, grills, ovens, stoves Over-exposure -> cell damage - Sun burn Night-vision equipment Remote controls Car security systems |
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Visible light |
Vision Photography Photosynthesis |
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UV-light |
Emitted by hot <4000 degrees objects
Sun (major source) Skin cancer and eye damage Some are reflected by the ozone layer UVA, UVB and UVC Detect forgeries of banknotes Destroy bacteria in water chillers |
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X-rays |
Cause cancer Diagnosis (medicine) Pass through soft tissue, stopped by bones Body scan (longer wavelength) |
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Gamma rays |
Shortest wavelength, most energy
High penetration Treatment of tumors Sterilising medical equipment Destroy virus and bacteria Disrupt DNA in cells - cause cancer Detect leaks from underground pipes Kill fungi and bacteria on fruit/vegetables |
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Absorption spectrum |
Light from stars can give information about gases that the light have passed on their way to Earth.
- "clouds of gases" in space or gases close to the surface of the stars Each gas (atom) will have their own colour that can be identified. EM radiation from space is observed from telescopes. There are different telescopes for different parts of the EM spectrum. |
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Greenhouse effect |
The process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be in the absence of its atmosphere. |
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Ozone layer |
Works as a filter for the UV radiation
15-40 kilometers above the Earth's surface O3 -UV radiation-> O2 + O O2 -UV radiation-> O + O O2 + O -UV radiation-> O3 |
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UV-radiation
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UVA, UVB, and UVC |
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UVA |
Gives us tan Longest wavelength Cause skin damage Less reflected by ozone layer |
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UVB |
Tan + red/burnt skin
Amount depends on thickness of the ozone layer, more reflected Skin damage |
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UVC |
Shortest wavelength (more energy) Most of it reflected by ozone layer |
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Ionising radiation |
Unstable nuclei. When particles will hit, electrons will be excited.
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Uses of radiation |
Finding the organisms age
Gamma radiation can treat tumors Sterilise surgical instruments and hospital dressings Beta radiation can monitor the thickness of a sheet of paper or aluminium |
