An X‑ray beam is incident normally on a sample of soft tissue and bone as shown in the figure below.
Data for the two materials are given in the table below.
The total thickness of soft tissue is 
. The total thickness of bone is also . The incident intensity of the X‑ray beam is 
. The transmitted intensity of the X‑ray beam is 
of the incident intensity. Determine , in 
.
Define the specific acoustic impedance of a medium.
Use data from the table above to calculate the percentage of the intensity of ultrasound that is transmitted at a boundary between soft tissue and bone.
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