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Define the following terms: wave, frequency, period Draw a simple sine waveform and label these: amplitude, wavelength, crest, trough. Define the following terms: Superposition Constructive interference Destructive interference Standing wave Nodes Antinodes. The Properties of Waves - PowerPoint PPT Presentation
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1. Define the following terms: wave, frequency, period
2. Draw a simple sine waveform and label these: amplitude, wavelength, crest, trough
Define the following terms: 1) Superposition2) Constructive interference3) Destructive interference4) Standing wave5) Nodes6) Antinodes
The Properties of Waves1. Reflection2. Refraction
3. Superposition4. Diffraction
Have you ever experienced having a really bad cell phone reception in the middle of an open, urban area?
Question:
What happens when a wave meets another wave?
Wave + Wave = ?
Superposition (Interference)• Two waves can be ‘added’ together
• Constructive interference occurs when the two waves are in phase (i.e. crests meet crests, troughs meet troughs)
• Destructive interference occurs when they are 180 degrees out of phase (i.e. crests meet troughs)
Constructive Interference (Antinode)
Destructive Interference (Node)
Ruben’s Tube
Standing Wave, Nodes and Antinodes• Wave produced by the superposition of
two equal but opposite waves
• Antinodes – places where constructive interferences occur (double crest and double trough)
• Nodes – places where destructive interferences occur (crest + trough = zero displacement)
Interference Pattern• Anti-nodes are formed when constructive
interferences occur where two waves are in phase because the path differences are whole numbers (0, 1, 2, 3…).
• Nodes are formed when destructive interferences occur where two wave are 180o out of phase because the path differences are ½, 1½, 2½, 3½…
Constructive Interference
Destructive Interference
Anti Nodes (anti nodal line)
Nodes (nodal line)
Crest + CrestTrough + Trough
Crest + Trough
In phase 180o out of phasePath differences are 0, 1, 2, 3, 4…
Path differences are ½, 1½, 2½, 3½…