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 the sound is 1.7km/s . The operating frequency of the scanner is 4.2MHz. [ 1MHz = 106 Hz] (2 marks)
Speed of the sound, v= 1.7km/s = 1700 m/s
Operating frequency of the scanner, f = 4.2MHz = 4.2*106 Hz
Wavelength of the sound , λ = ?
We know, v = f λ
=> λ = v/f = 1700/(4.2*106) = 0.405 mm