Practice Echo Questions

Question 1

What is the wavelength for a sound wave with a frequency of 1.6 MHz?

Answer 1

C (Speed of sound) = Wavelength * Frequency

C = ~1600 cm/sec

Answer = 1 mm or 0.001 meters

Question 2

What medium does an ultrasound wavae result in the fastest loss of it’s strength?

Answer 2

Lung

Why? –> High content of air and the abundaance of highly reflextive tissue/air interfaces (Sound waves dissipate in the lung so fast that the lungs are virtually opaque to ultrasound)

Question 3

Why do we use ultrasound gel?

Answer 3

Improve contact between transducer surface and the skin by eliminating any tissue/air interfaces, which are highly reflective and thus prevent transmission into the body