A standing wave is created in an open pipe that is open at both ends and placed within a chamber filled with an unknown gas. The pipe has a length of 45 cm and the fundamental frequency in this pipe is 381 Hz.
A speaker is set-up directly above the top of a vertical pipe which is partially filled with water.
Initially, there is a strong sound heard from the pipe when the distance between the loudspeaker and the water is 83 cm. This is the longest length for which a strong sound is heard.
As the pipe is filled with more water, a second strong sound is heard from the pipe when the distance between the loudspeaker and the water is 67 cm.
(a)
Outline how a standing wave is created between the speaker and the surface of the water.
The air within the pipe and the water at the bottom of the pipe are both heated to 70 . The speed of sound in this warmer air is 371 m s−1 and the speaker now plays a sound at a constant frequency of 600 Hz.
(c)
The speaker is brought down to the surface of the water and slowly raised until a strong sound is produced. The distance between the surface of the water and the speaker is 15.5 cm when this occurs. State what is causing the strong sound and estimate the wavelength of this sound.
If the water volume is kept constant, predict the distance that the speaker must be raised for the next strong sound to be produced and outline what causes this strong sound.
On the diagram shown, draw the stationary wave that would be formed on the string in part (b) with two more nodes and two more antinodes. State the harmonic of this new stationary wave.
The diagram represents a stationary wave formed on a violin string fixed at P and Q when it is plucked at its centre. X is a point on the string at maximum displacement.
(a)
Explain why a stationary wave is formed on the string.
The diagram shows the appearance of a stationary wave on a stretched string at one instant in time. In the position shown each part of the string is at a maximum displacement.
(a)
Mark clearly on the diagram the direction in which points Q, R, S and T are about to move.
