Standing waves: nodes, antinodes and superposition
Practice Flashcards
Flip to reveal answersWhat is a standing (stationary) wave?
Track your progress — Sign up free to save your progress and get smart review reminders based on spaced repetition.
All 12 Flashcards — Standing waves: nodes, antinodes and superposition
Sign up free to track progress and get spaced-repetition review schedules.
Question
What is a standing (stationary) wave?
Answer
The fixed pattern made when **two identical waves travel in opposite directions** and superpose — it does not move along.
Question
What is superposition?
Answer
When two waves overlap, you **add their displacements** at every point to get the total wave.
Question
Define a node.
Answer
A point on a standing wave that **never moves** (zero displacement) — the two waves always cancel there.
Question
Define an antinode.
Answer
A point on a standing wave that swings with the **largest amplitude**, halfway between two nodes.
Question
How far apart are neighbouring nodes?
Answer
**Half a wavelength (λ/2).** So λ = 2 × the node-to-node spacing. (Not in the data booklet — remember it.)
Question
Does a standing wave transfer energy along its length?
Answer
**No** — there is no net energy transfer along a standing wave; the energy stays stored in place.
Question
Phase of points between two nodes?
Answer
They move **in phase** (all together). Points on opposite sides of a node move in **antiphase** (exactly opposite).
Question
Standing wave vs travelling wave — phase?
Answer
Standing: points are only ever **in phase or antiphase**. Travelling: the phase shifts **smoothly** from point to point.
Question
How is a standing wave usually produced?
Answer
A wave **reflects off a fixed end** and meets itself coming back — two identical opposite waves that superpose.
Question
Why does chocolate melt in spots in a microwave?
Answer
Microwaves reflect off the walls and form a **standing wave**; the field is strongest at the **antinodes**, so it melts there and stays solid at the nodes.
Question
Melted spots are 6.0 cm apart — what is the wavelength?
Answer
Spots are one antinode apart = λ/2, so λ = 2 × 0.060 = 0.12 m.
Question
Most common standing-wave mistake?
Answer
Thinking it **carries energy along** the string, or halving (instead of doubling) the node spacing to get the wavelength.
Read the notes
Full study notes for Standing waves: nodes, antinodes and superposition
Topic 3.4 hub
Standing waves and resonance
More from Topic 3.4
All flashcards in this topic
Physics exam skills
Paper structures & tips
Track your progress with spaced repetition
Sign up free — Aimnova tells you exactly which cards to review and when, so you remember everything before your IB exam.
Start Free