Question

a) Verbally describe how standing waves look for a string? A pipe that is open at both ends? A pipe that is closed at one end and open at the other?

b) What produces the vibrations in various string instruments?

c) How do the wavelength and frequency of a sound change if they are emitted by an object (such as an automobile) which is moving away from you? Towards you?

Please type your responses for better legibility.

Answer 1

a) A standing wave is established over a stretched string such that Nodes and Antinodes are formed on it. Nodes are the points of zero displacement and Antinodes are the points of maximum displacement. DostaDis between two consecutive nodes or Antinodes are equal to half of wavelength of the waves whose superposition gives the stationary waves.

In a closed end organ pipe, there is always an Antinode at open end and Node at closed end.

In an open end organ pipe there is antinoAnt at both the open ends. Frequency in open end organ pipe is twice to that in closed end organ pipe.

b) in string instruments, vibrating strings make wind columns to vibrate and create sound

C) If the automobile is moving away from us, its frequency will appear to be reduced and wavelength to be increased, on the other hand, if automobile is approaching us, frequency will increase while wavelength will decrease