William Heathcote Solutions for Chapter: Consequences, Exercise 9: Data-based question: Ultrasound imaging

Ultrasound imaging is a useful, non-invasive way of seeing inside the body. For example, to monitor a pregnancy using ultrasound imaging, a transducer is placed against the mother's abdomen. This emits ultrasound waves and detects the echo as they bounce off the foetus. The ultrasound has a frequency of about $2.5 MHz$ and the waves travel at about $1,500 m s^{-1}$.Calculate the wavelength (in micro meter) of the ultrasound.

Ultrasound imaging is a useful, non-invasive way of seeing inside the body. For example, to monitor a pregnancy using ultrasound imaging, a transducer is placed against the mother's abdomen. This emits ultrasound waves and detects the echo as they bounce off the foetus. The ultrasound has a frequency of about $2.5 MHz$ and the waves travel at about $1,500 m s^{-1}$.The image is built up by sending ultrasound waves and measuring the time between the emission of the waves and the detected echo. If the waves bounce off an object that is $3 cm$ away from the transducer, what is the time delay between the ultrasound wave being emitted and the echo being received?

Discuss the advantages and disadvantages of invasive and non-invasive techniques for monitoring unborn babies.