Ultra Sound Flashcards Preview

Physics > Ultra Sound > Flashcards

Flashcards in Ultra Sound Deck (11):
1

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

=0.33

2

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

3

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

4

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

Systematic error

5

What is ultrasound

Sound waves above 20,000 Hz

6

Why must the ultrasound beam be narrow and focused

Target specific areas

7

Advantage of using gel on the skin during ultrasound

Allows sound waves to transmit into the body

8

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

To create cross sections

9

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

Allow reflections back to the transducer (sir clapping)

10

Why does an ultrasound of a beating heart keep changing

Because the heart moves/pulses

11

Disadvantage of using gel on the skin (ultrasound)

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