Question

Diagnostic ultrasound of frequency 4.80 MHz is used to examine tumors in soft tissue.
(a) What is the wavelength in the air of such a sound wave?
(b) If the speed of sound in tissue is 1500m/s, what is the wavelength of this wave in tissue? (Hint: the speed of sound wave in air is always 343m/s)

Answer 1

Answer:

0.0000714583 m

0.0003125 m

Explanation:

v = Speed of sound in the medium

f = Frequency = 4.8 MHz

Wavelength is given by

$\lambda=\dfrac{v}{f}\\\Rightarrow \lambda=\dfrac{343}{4.8\times 10^6}\\\Rightarrow \lambda=0.0000714583\ m$

Wavelength of the sound in air is 0.0000714583 m

$\lambda=\dfrac{v}{f}\\\Rightarrow \lambda=\dfrac{1500}{4.8\times 10^6}\\\Rightarrow \lambda=0.0003125\ m$

Wavelength of the sound in the tissue is 0.0003125 m