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-Waves at Boundaries -Reflection -Interference of Waves. Physics Mrs. Coyle. Coyle, Greece, 2009, Island of Antipaxos. How is the speed of a wave affected when a wave enters from one medium to another?. The speed depends on the medium. It does not depend on frequency and amplitude.
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-Waves at Boundaries-Reflection -Interference of Waves Physics Mrs. Coyle Coyle, Greece, 2009, Island of Antipaxos
How is the speed of a wave affected when a wave enters from one medium to another? • The speed depends on the medium. • It does not depend on frequency and amplitude. • It remains constant in a given medium at the same conditions. • When a wave enters a different medium, its speed changes but its frequency remains the same.
Speed of a Wave, v =lf • For a given medium, v=constant.
What does a high or low amplitude indicate? Low Amplitude High Amplitude
What happens when a wave reaches a boundary? • Part of the incident wave is transmitted and part of it is reflected.
Pulse travelling from less dense to more dense medium. • What happens to the pulse at the interface? http://www.dacc.edu/~qchen/P102/labs/LAB5.HTM
Reflection of a Pulse from a Fixed End What is the direction of the reflected pulse? http://www.dacc.edu/~qchen/P102/labs/LAB5.HTM
Reflection of a Wave from a Fixed End: the pulse returns inverted http://openlearn.open.ac.uk/file.php/3524/TA212_2_008i.jpg
Reflection of a Pulse from a Free End What is the direction of the reflected pulse? http://www.dacc.edu/~qchen/P102/labs/LAB5.HTM
Wave on a String • (Applet) http://phet.colorado.edu/sims/wave-on-a-string/wave-on-a-string_en.html
Interference • When two pulses pass the same point at the same time the waves superimpose either constructively or destructively. • Constructive Interference • Destructive Interference
Constructive Interference: resulting wave has a greater amplitude.
Destructive Interference: Resulting wave has a smaller amplitude.
The displacements are added algebraically at the given point in time.
Interference http://ircamera.as.arizona.edu/NatSci102/NatSci102/movies/interference.gif
Superposition • Simulation: Constructive and Destructive Interference (string with loose or fixed end) • http://www3.interscience.wiley.com:8100/legacy/college/halliday/0471320005/simulations6e/index.htm?newwindow=true