Question: Diagnostic ultrasound of frequency is 4.50 MHz used to examine tumors in soft tissue. (a) What is the wavelength in air of such a sound wave? (b) If the speed of sound in tissue is , what is the wavelength of this wave in tissue?

Question: Two spectators at a soccer game see, and a moment later hear, the ball being kicked on the playing field. The time delay for spectator A is, 0.23 s and the spectator B it is 0.12s. Sight lines from the spectators to the player kicking the ball meet at an angle of. How far are (a) spectator and (b) spectator from the player? (c) How far are the spectators from each other?

The sixth harmonic is set up in a pipe. (a) How many open ends does the pipe have (it has at least one)? (b) Is there a node, antinode, or some intermediate state at the midpoint?

Two identical tuning forks can oscillate at $\mathbf{440}\mathbf{\text{\hspace{0.17em}Hz}}$. A person is located somewhere on the line between them. Calculate the beat frequency as measured by this individual if (a) she is standing still and the tuning forks move in the same direction along the line at, $\mathbf{3}\mathbf{.00}\mathbf{\text{\hspace{0.17em}m}}\mathbf{/}\mathbf{\text{s}}$ (b) the tuning forks are stationary and the listener moves along the line at $\mathbf{3}\mathbf{.00}\mathbf{\text{\hspace{0.17em}m}}\mathbf{/}\mathbf{\text{s}}$.

Two sound waves with amplitude of $\mathbf{12}\mathbf{\text{\hspace{0.17em}nm}}$and a wavelength of $\mathbf{35}\mathbf{\text{\hspace{0.17em}cm}}$travel in the same direction through a long tube, with a phase difference of $\mathit{\pi }\mathbf{/}\mathbf{3}\mathbf{\text{\hspace{0.17em}rad}}$. What are the (a) amplitude and (b) wavelength of the net sound wave produced by their interference? If, instead, the sound waves travel through the tube in opposite directions, what are the (c) amplitude and (d) wavelength of the net wave?

At a certain point, two waves produce pressure variations given by $\mathit{\Delta }{\mathit{p}}_{\mathbf{1}}\mathbf{=}\mathit{\Delta }{\mathit{p}}_{\mathbf{m}}\mathbf{}\mathit{s}\mathit{i}\mathit{n}\mathbf{}\mathit{\omega }\mathit{t}$ and $\mathit{\Delta }{\mathit{p}}_{\mathbf{2}}\mathbf{=}\mathit{\Delta }{\mathit{p}}_{\mathbf{m}}\mathbf{}\mathit{s}\mathit{i}\mathit{n}\mathbf{(}\mathbf{\omega }\mathbf{t}\mathbf{}\mathbf{-}\mathbf{\varphi }\mathbf{)}$ .At this point, what is the ratio$\mathit{\Delta }{\mathit{p}}_{\mathbf{r}}\mathbf{/}\mathit{\Delta }{\mathit{p}}_{\mathbf{m}}$ , where $\mathit{\Delta }{\mathit{p}}_{\mathbf{r}}$ is the pressure amplitude of the resultant wave, if f is (a) 0 , (b) $\mathit{\pi }\mathbf{/}\mathbf{2}$ , (c) $\mathit{\pi }\mathbf{/}\mathbf{3}$, and (d) $\mathit{\pi }\mathbf{/}\mathbf{4}$?