I keep getting “Standing waves” questions wrong in Waves & Sound. What's the trap?
placing a node and adjacent antinode half a wavelength apart.
The usual trap: placing a node and adjacent antinode half a wavelength apart. How to avoid it: node to next antinode is lambda/4; node to node is lambda/2. Go back to the definition — Two identical waves travelling oppositely form fixed nodes of zero displacement and antinodes of maximum displacement. A standing wave stores a spatial pattern and has no net energy transport along the medium.
Key point
Standing waves
Common mistake
placing a node and adjacent antinode half a wavelength apart.
Memory tip
node to next antinode is lambda/4; node to node is lambda/2.
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