Question

A hospital uses an ultrasonic scanner to locate tumours in a tissue. What is the wavelength of sound in the tissue in which the speed of sound is $1.7km{s}^{-1}$? The operating frequency of the scanner is 4.2 MHz.

Answer 1

Speed of sound in the tissue, v = 1.7 km/s =$1.7\times {10}^{3}m/s$
Operating frequency of the scanner, $\nu =4.2MHz=4.2\times {10}^{6}Hz$
The wavelength of sound in the tissue is given as:
$\lambda =\frac{v}{\nu }=\frac{1.7\times {10}^3}{4.2\times {10}^6}=4.1\times {10}^{-4}m$