Standing Waves Revision

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?

• 3.6 m s^–1

• 7.2 m s^–1

• 360 m s^–1

• 720 m s^–1

A loudspeaker emitting sound of frequency f is placed at the open end of a pipe of length l which is closed at the other end. A standing wave is set up in the pipe.

A series of pipes are then set up with either one or two loudspeakers of frequency f. The pairs of loudspeakers vibrate in phase with each other.

Which pipe contains one standing wave?

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The table contains statements about stationary and progressive waves.

Which row is correct?

• A

• B

• C

• D

A stationary sound wave is produced in a tube.

Which statement describes the wave speed?

• It is the distance between two adjacent nodes divided by the period of the wave.

• It is the speed at which energy is transferred from one antinode to an adjacent antinode.

• It is the speed of a particle at an antinode.

• It is the speed of one of the progressive waves that are producing the stationary wave.

An organ pipe of length l is open at both ends. Notes are produced by the pipe when stationary waves are set up.

The speed of sound in the air column is v.

What is the lowest (fundamental) frequency of the note produced by the pipe?

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A stationary wave on a stretched string is set up between two points P and T.

Which statement about the wave is correct?

• Point R is at a node.

• Points Q and S vibrate in phase.

• The distance between P and T is three wavelengths.

• The wave shown has the lowest possible frequency.

The basic principle of note production in a horn is to set up a stationary wave in an air column.

• A

• B

• C

• D

The diagram shows a sketch of a wave pattern, over a short period of time.

Which description of this wave is correct?

• The wave is longitudinal, has a wavelength of 20 cm and is stationary.

• The wave is transverse, has a wavelength of 20 cm and is stationary.

• The wave is transverse, has a wavelength of 40 cm and is progressive.

• The wave is transverse, has a wavelength of 40 cm and is stationary.