Physics 9702 · AS & A Level · Stationary waves

Stationary waves — practice question

A vertical tube of length $0.60\,\text{m}$ has both ends open. A sinusoidal incident sound wave of a single frequency moves upward through the tube. A stationary wave is then established in the air column, with antinodes at both ends and a node at the midpoint, as shown in Fig. 5.1.
(a)[2]

Explain how the stationary wave is formed from the incident sound wave.

(b)[2]

On Fig. 5.2, sketch a graph to show how the amplitude of the stationary wave varies with height $h$ above the bottom of the tube.

(c(i))[1]

For the stationary wave, state the direction in which an air particle oscillates at a height of $0.15\,\text{m}$ above the bottom of the tube.

(c(ii))[1]

For the stationary wave, state the phase difference between the oscillations of a particle at a height of $0.10\,\text{m}$ and a particle at a height of $0.20\,\text{m}$ above the bottom of the tube.

(d)[2]

The speed of the sound wave is $340\,\text{m s}^{-1}$. Calculate the frequency of the sound wave.

(e)[1]

The frequency of the sound wave is increased gradually. Determine the frequency of the wave when the next stationary wave is formed.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: The (incident) wave reflects at the end/top of the tube

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI