(a)[6]
Explain the key principles involved in using ultrasound to get diagnostic information about internal body structures.
(b(i))[2]
Define specific acoustic impedance.
(b(ii))[2]
Two media have specific acoustic impedances $Z_1$ and $Z_2$. Their values may be almost the same or very different. State how these differences change the intensity reflection coefficient at the boundary between the two media for the cases $Z_1 \approx Z_2$ and $Z_1 \gg Z_2$ or $Z_1 \ll Z_2$.