revision unit 9 Flashcards
what re sound waves
they are vibrations that travel through a medium. they are longitudinal and they cant travel through a vacuum
how are echo are caused nd how can you stop them
they are caused by sound waves reflecting off a smooth, hard surface, you can stop echo by covering the wall with soft fabric to absorb it instead and by not having smooth surfaces as the sound would be reflected it would be diffracted
increasing the frequency would increase?
increase the pitch of the sound
increasing the amplitude would increase
the loudness of the sound
how is sound waves produced form musical instruments
when played they would vibrate creating sound waves
what is ultra sound
are sound waves that are above 20 000hz which is above the human hearing range
how does ultrasound work for the babies in the womb
the ultrasound has a control system, a transducer, and a display screen where each pulse from the transducer is partially reflected at different tissue boundaries, as the pulses would return would return to the transducer a a series of reflected pulses from different boundaries, arriving at different times, so when a transducer is placed across the stomach it would release the pulses and once they are reflected they would be picked up by the transducer as they are used to build an image
what is the advantage of using ultrasound
- it is non ionizing
2. it can scan organs and different soft tissues
what is a-scan
it is a ultraviolet scan used to find the length of something i.e. eye
how can you use an a a-scan to find the length of the eye
a transducer is placed on top of the eye as it sends ultraviolet waves that are reflected and picked up by the transducer and shown on a oscilloscope which is used to find the transit time which is the time it takes a ultraviolet wave to be reflected from a boundary to the transducer, then you would calculate the distance by: transit time x speed of wave and then you can can calculate the depth = 1/2 x transit time x speed and you can do that since the pulse travels from the boundary back to the transducer so depth is half the distance
how can you use ultraviolet waves to treat kidney stone
a very strong ultraviolet wave would be applied to the kidney stone breaking it into smaller fragments that can be removed naturally
