Question

During an ultrasound, sound waves are sent by a transducer through muscle tissue at a speed of 1300 m/s. Some of the sound waves are reflected from a metal fragment 3.0 cm into the muscle tissue. How long did it take the transducer to detect the reflected waves from the metal fragment after they were first emitted?
23 seconds
39 seconds
2.3 x 10−5 seconds
3.9 x 10−5 seconds

Answer 1

Answer: $2.3(10)^{-5} s$

Explanation:

The velocity $V$ of the sound wave in the muscle tissue. which is the same as the reflected from a metal fragment is:

$V=\frac{d}{t}$

Where:

$V=1300 m/s$

$d=3 cm \frac{1m}{100 cm}=0.03 m$ is the distance traveled by the sound wave

$t$ is the time

Isolating $t$:

$t=\frac{d}{V}$

$t=\frac{0.03 m}{1300 m/s}$

Finally:

$t=2.3(10)^{-5} s$