
A parallel beam of ultrasound of intensity
is incident normally on a muscle of thickness
, as shown in the figure below.
The ultrasound wave is reflected at a muscle-bone boundary. The intensity of the ultrasound received back at the transducer is
. Some data for bone and muscle are given in the table below.
The intensity reflection coefficient
for two media having specific acoustic impedances
and
is given by

Calculate the fraction of the ultrasound intensity that is reflected at the muscle-bone boundary.
Calculate the fraction of the ultrasound intensity that is transmitted through a thickness of
of muscle.
Use your answers in (a) and (b) to determine the ratio
.