1.11k likes | 1.36k Views
Topic 11: Wave phenomena. 11.1 Standing (stationary) waves. 11.1.1 Describe the nature of standing (stationary) waves. Students should consider energy transfer, amplitude and phase. Formation of standing waves. The reflected wave is 180 º phase shifted.
E N D
11.1 Standing (stationary) waves 11.1.1 Describe the nature of standing (stationary) waves. Students should consider energy transfer, amplitude and phase.
Boundary conditions on a string Click to play Pulse
Boundary conditions for a wave Click to play
Nodes and antinodes λ Hyperlink
Modes of vibration in strings Hyperlink λ λ
Standing waves on a string Click to play Fixed / free Free / free Fixed / fixed
Set up this experiment and produce the first 8 standing waves. Record the wavelength for each one. Record the frequency for each resonant standing wave. Plot a suitable graph to determine the relationship between frequency and wavelength.
Modes of vibration in pipes Closed pipe i.e. node at one end and antinode at the other Open pipe i.e. Antinode at both ends. Hyperlink
A 0.3 m section of discarded garden hose will produce a trumpet sound when blown as one blows a trumpet. Changing the length will change the pitch of the "trumpet".
Measurement of velocity of sound Measure difference in length between 2 successive resonances. Use this distance to calculate the wavelength. Use this value and the frequency of the tuning fork to calculate the speed of sound.
Questions from Tsokos • Page 256 Questions 1 – 6,8,10-14.
The Doppler effect Johann Christian Doppler1803-1853 The diagram below represents waves emitted by a source of sound, S, which is stationary relative to the air. The velocity of the sound waves relative to the air is v.
Doppler wavefronts Click to play
Explain the Doppler effect by reference to wavefront diagrams for moving-detector and moving-source situations.
The next diagram represents waves emitted by a source which is moving(with velocity vs) relative to the air. λ λ Speed same, frequency and wavelength change Motion of the source produces a change in the wavelength, longer wavelength behind, shorter wavelength in front of source.
Doppler effect for sound Hyperlink
Moving observer Wavelength fixed, speed and frequency change
Doppler shift for SOUND source Be careful to apply the + or – the correct way.