With reference to the direction in which energy is transferred, compare the oscillations of transverse and longitudinal progressive waves.
On Fig. 4.1, add a letter A at the position of an antinode.
The speed of sound in air is $340\,\text{m s}^{-1}$. Determine the frequency of the sound wave.
A pipe is open at one end and closed at the other by a piston. The piston can move freely and is at a distance of $4.5 \times 10^{-2}\,\text{m}$ from the open end of the pipe. A loudspeaker is placed near the open end of the pipe and produces a sound wave of one constant frequency. A stationary wave is set up in the pipe, as shown in Fig. 4.1.
The piston is moved to the left. The frequency of the sound wave emitted by the loudspeaker is then changed so that a stationary wave is formed with the same number of antinodes as in Fig. 4.1. State and explain the change that is made to the frequency of the sound wave.