Physics- P6 Part D

1. ... is sound with frequencies above 20,000 Hz. They get partially reflected at boundaries- some is transmitted, some is reflected. Time taken to reach a detector determines how far away the boundary is (10)
6. Seismic Wave: Transverse wave, can't travel through liquids or gases, slower than the other type of seismic wave. (1, 5)
7. Ultrasound use: Find flaws in objects like pipes or wood and metal. Ultrasound waves are reflected from far side of material. If there is a flaw e.g. a crack, wave is reflected sooner (10, 7)
8. Seismic wave: Longitudinal, travel through solids and liquids and are faster than the other type of seismic wave (1, 5)
9. ... sounding uses high frequency sound waves. used by boats and submarines to find depth of water or find objects in deep water (4)

2. Waves have different ... depending on material they are travelling through. Meeting a boundary can result in: -Partial or total reflection -Refraction or absorption -Change of speed. Using different waves helps to study ... of materials we cant see (10)
3. ... are caused by vibrating objects. Vibrations are passed through surroundings as compressions and rarefractions. They travel faster in solids, than liquids, slowest in gas- cause particles to vibrate in solids. Space is a vacuum, ... can't travel (5, 5)
4. Sound waves that reach your ... cause it to vibrate. Vibrations are passed on to tiny bones (ossicles), then the semi-circular canals and to the cochlea. Cochlea turns vibrations into electrical signals which go to the brain. (3, 4)
5. Overall ... of earth depends on how much radiation has been absorbed, transmitted or reflected. During the day there is an increase in ... as lot's of radiation is absorbed by earth from sun. During the night, there is a decrease in ... (11)
10. ... is the power per unit area. A temperature increases, ... of emitted wavelengths increase. ... increases more rapidly for shorter wavelengths (9)

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