Question

a hospital uses an ultra sonic scanner to locate tumours in a tissue what is the wavellength o f sound in a tissue in which the speed of sound is 1.7km/s the operating frequency of scanner is 4.2MHz

Answer 1

Given ;
v = 1.7 Km/s = 1700 m/s
f = 4.2 MHz = 4200000 Hz

v = frequency×Wavelength
1700 = 4200000 × Wavelength

Wavelength
= 1700/4200000
= 0.0004 m
____;___________

Answer 2

Whenever we solve problems we should bring down the given information in its SI unit.

Speed of sound,s = 1.7km/s = 1700m/s
Frequency = 4.2MHz = 420000Hz

Wavelength = Speed/Frequency
= 1700/4200000
= 0.0004m