On Fig. 4.1, circle two particles that are exactly one wavelength apart.
On Fig. 4.1, sketch a line on the graph to show the particle displacements for the longitudinal wave at time $t_0 + \frac{T}{4}$.
State the direction in which particle $Z$ is moving at time $t_0 + \frac{T}{4}$.
The frequency of the wave in (a) is $16\,\text{kHz}$. The separation between particles $X$ and $Y$ is $0.19\,\text{m}$. Calculate the speed at which the wave moves through the medium.
A longitudinal sound wave is travelling through a solid. Its initial intensity is $I_0$. The frequency stays constant and the amplitude drops to half of its original value. Determine the final intensity of the wave in terms of $I_0$.
The sound wave in (c) now meets a second sound wave moving in the opposite direction. State one condition needed for these two waves to form a stationary wave.
State two differences between a stationary wave and a progressive wave.