1) The three waves shown in each diagram have the same amplitude and frequency but differ in phase.

They are added together to give a resultant wave.

In which case is the resultant wave zero?

2) The diagram represents the pattern of stationary waves formed by the superposition of sound waves from a loudspeaker and their reflection from a metal sheet (not shown).

W, X, Y and Z are four points on the line through the centre of these waves.

Which statement about these stationary waves is correct?

3) Where, in a standing wave, do the vibrations of the medium occur?

4) A stationary wave is set up on a stretched string, as shown.

Which statement about the points on the string is correct?

5) A stationary wave is produced by two loudspeakers emitting sound of the same frequency.

When a microphone is moved between X and Y, a distance of 1.5 m, six nodes and seven antinodes are detected.

What is the wavelength of the sound?