This is a sample of our (approximately) 4 page long Waves notes, which we sell as part of the Physics AS Level Notes collection, a A package written at Manchester High School For Girls Sixth Form in 2013 that contains (approximately) 36 pages of notes across 13 different documents.
The following is a plain text extract of the PDF sample above, taken from our Physics AS Level Notes. This text version has had its formatting removed so pay attention to its contents alone rather than its presentation. The version you download will have its original formatting intact and so will be much prettier to look at.
Unit 2: 12 Waves
WAVES Progressive Waves transfer energy without any transfer of matter by the vibration of a medium. Classiﬁcation of waves;
- MECHANICAL WAVES involve the vibration of particles.
- ELECTROMAGNETIC WAVES involve the vibration of electric and magnetic ﬁelds. or
- TRANSVERSE WAVES have vibrations perpendicular to the direction of energy transfer.
- LONGITUDINAL WAVES have vibrations parallel to the direction of energy transfer. EXAMPLES
Water Waves Seismic Waves Slinky/Spring
Seismic P Waves Sound Slinky/Spring
POLARISATION; UNPOLARISED LIGHT sources produce light waves in which the direction of oscillation of the electric ﬁeld is constantly changing.
POLAROID FILTERS only transmit light that his its electric
ﬁeld oscillating in a particular direction.
POLARISATION OCCURS ONLY WITH TRANSVERSE WAVES (since transverse waves oscillate perpendicular to the direction energy transfer). POLARISATION is the only phenomenon which can be used to distinguish between longitudinal and transverse waves Applications of Polarisation
1. To reduce glare - unpolarised light can be partially polarised when reﬂected off a surface. A polaroid ﬁlter on sunglasses etc can cut out this polarised light, reducing glare.
2. Photo-elastic Stress Analysis - a transparent object viewed between crossed polaroid ﬁlters shows a series of coloured lines. These lines indicate regions of stress, with the greatest stress being where the lines are most concentrated. Engineers use this phenomenon to identify regions of stress in structures by building models in perspex and then viewed the stress lines.
3. Transmission of TV/Radio Signals - Signals sent out from dishes can be given different angles of polarised light so that the signals do not interfere with each other. For examples, horizontally polarised signals will not interfere with vertically polarised light.
PHYSICS AS NOTES
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