Question

A hospital uses an ultrasonic scanner to locate tumours in a tissue what is the wavelength of ultrasound if speed =1.5km/s and frequency=4mHz

Answer 1

WKT 
v=n * lambda
v=1.5km/s = 1500m/s
wave length = 4mHz =4 000 000 Hz = 4x $10^{6}$ Hz
n= 1500/ 4x $10^{6}$
= 3.75 x $10^{-4}$ m