(a(i))[1]
State what acoustic impedance means for a medium.
(a(ii))[1]
Fig. 10.1 gives data for several media. Use the figures in Fig. 10.1 to work out the density of bone.
(b(i))[1]
State the link between $I$, $I_T$ and $I_R$.
(b(ii).1)[2]
The reflection coefficient $\alpha$ is given by $\alpha = \frac{(Z_2 - Z_1)^2}{(Z_2 + Z_1)^2}$. Use the data in Fig. 10.1 to find the reflection coefficient $\alpha$ for the boundary between gel and soft tissue.
(b(ii).2)[1]
The reflection coefficient $\alpha$ is given by $\alpha = \frac{(Z_2 - Z_1)^2}{(Z_2 + Z_1)^2}$. Use the data in Fig. 10.1 to find the reflection coefficient $\alpha$ for the boundary between air and soft tissue.
(c)[3]
Explain, with reference to your answers in (b)(ii), why gel is used on the skin surface during ultrasound diagnosis.