1) To produce a stationary wave, two waves must travel in opposite directions through the same space.

Which statement about the properties of the two waves must also be true?

2) A stationary longitudinal wave is set up in a pipe.

In the diagrams below, the length of each arrow represents the amplitude of the motion of the air molecules, and the arrow head shows the direction of motion at a particular instant.

Which diagram shows a stationary wave in which there are two nodes and two antinodes?

3) 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?

4) The diagram shows a stationary wave on a string at two instants of maximum vertical displacement.

The frequency of the wave is 12 Hz.

What is the speed of the wave?

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

Which statement about the points on the string is correct?