Ultra Sound Flashcards Preview

Physics > Ultra Sound > Flashcards

Flashcards in Ultra Sound Deck (11):

A block with a crack inside is scanned with a ultrasound.

Work out distance to the object (crack) reflecting the ultrasound.

-The speed of sound in air is 330 m/s
-time taken for reflection to return (s): 0.002

0.002 x 330= 0.66 (distance traveled to and back from crack)

0.66/2 = 0.33 m



Why is it important to calibrate the sensors on a submarine for sea water or for fresh water

-Sea water is dense so faster results
-wouldn’t give correct speed


What would happen if the sea water settings were used to determine the depth of a fresh water lake?

It will think the waters deeper
-bigger number for sound


What error would using the wrong settings introduce to a collection of data

Systematic error


What is ultrasound

Sound waves above 20,000 Hz


Why must the ultrasound beam be narrow and focused

Target specific areas


Advantage of using gel on the skin during ultrasound

Allows sound waves to transmit into the body


Why is the probe move around during the scan(ultrasound)

To create cross sections


Why is a series of ultrasound pulses used instead of a continuous beam

Allow reflections back to the transducer (sir clapping)


Why does an ultrasound of a beating heart keep changing

Because the heart moves/pulses


Disadvantage of using gel on the skin (ultrasound)

Some waves are reflected due to changes in layers of thickness(skin)