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gcse science P4 - D
specific for ocr gateway additonal science B.
| Question | Answer |
|---|---|
| what is frequency in sound waves? what is frequency linked to? | -number of waves produced each second -pitch |
| what is amplitude in sound waves linked to? | loudness |
| what is compressions in sound waves? | area where particles are close together |
| what is ultrasound produced by? | vibrating particles that form a longitudinal wave |
| what are the features of a longitudinal wave? | -they can't travel through a vacuum. the denser the medium, the faster a wave travels -the higher the frequency or pitch, the smaller the wavelength -the louder the sound/the more powerful the ultrasound, the larger the amplitude |
| what is ultrasound? | a sound of a higher frequency that humans can't hear |
| what does ultrasound travel as? | a pressure wave - compressions and rarefactions |
| what are the vibrations of particles like in a longitudinal wave? | they are in the same direction as the wave |
| what are the vibrations of particles like in a transverse wave? | they are at right angles to the direction of the wave |
| what are the main 2 uses of ultrasound? | -to break down kidney stones -in a body scan |
| how does ultrasound work in the process of breaking down kidney stones? | -high powered ultrasound beam is directed at kidney stones -ultrasound energy breaks the stones into smaller pieces -tiny pieces are then excreted from the body in a normal way |
| how does ultrasound work in the process of a body scan? | -pulse of ultrasound is sent to the body -at each boundary between different tissues, some ultrasound is reflected and the rest is transmitted -the returning echoes are recorded and used to build up an image |
| why can ultrasound be used for body scans?1 | reflections from boundaries of organs create echoes which build up the image |
| what happens if the tissues are very different, e.g. blood and bone? | most of the ultrasound is reflected, leaving very little to penetrate further into the body |
| why is ultrasound preferred to x-rays? | -differentiates between soft tissues better -doesn't damage living cells |
Created by:
jirwin
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