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 1.7 km s⁻¹? The operating frequency of the scanner is 4.2 MHz.

Answer 1

Given,
Frequency of operating scanner , f = 4.2MHz
f = 4.2 × 10^6 Hz

speed of sound in tissue , v = 1.7 km/s
v = 1.7 × 10³ m/s = 1700 m/s

use formula $v=\lambda f$ , To find wavelength of sound.

so, wavelength = speed of sound in tissue/frequency of operating scanner

= (1700/4.2 × 10^6)

= 4.1 × 10^-4 m

hence, wavelength of sound in tissue is 4.1 × 10^-4m