8.1 AS Level

Stationary waves

8 flashcards to master this topic

Definition Flip

State the principle of superposition.

Answer Flip

When two or more waves overlap in a region, the resultant displacement at any point is the vector sum of the displacements of the individual waves at that point.

Key Concept Flip

Describe how stationary waves are formed.

Answer Flip

Stationary waves are formed when two progressive waves, travelling in opposite directions, with the same frequency and amplitude, superpose. Interference results in points of maximum displacement (antinodes) and zero displacement (nodes).

Definition Flip

What is the distance between two adjacent nodes (or antinodes) in a stationary wave?

Answer Flip

The distance between two adjacent nodes (or antinodes) is half the wavelength (λ/2) of the wave.

Key Concept Flip

Explain how a stationary wave can be produced using microwaves.

Answer Flip

Microwaves are directed at a metal plate, causing reflection. The incident and reflected waves, having the same frequency and amplitude, superpose to form a stationary wave. A microwave detector can be used to locate nodes and antinodes.

Key Concept Flip

Describe an experiment to demonstrate stationary waves using a stretched string.

Answer Flip

A string is attached to a vibration generator at one end and passes over a pulley with a hanging mass at the other. By adjusting the frequency of the vibration generator, standing waves are created when an integer number of half-wavelengths fit along the string. The frequency at which resonance occurs is noted.

Calculation Flip

Explain how you can determine the wavelength of a stationary wave from the positions of its nodes.

Answer Flip

Measure the distance between several nodes, then divide by the number of internodal distances to find the average internodal distance. Since the distance between adjacent nodes is λ/2, multiply the internodal distance by 2 to find the wavelength λ.

Definition Flip

What is the difference between a node and an antinode in a stationary wave?

Answer Flip

A node is a point on a stationary wave where the displacement is always zero (destructive interference). An antinode is a point on a stationary wave where the displacement has maximum amplitude (constructive interference).

Key Concept Flip

How are stationary waves in air columns formed?

Answer Flip

Stationary waves can form in air columns (

Example: in a tube) due to the superposition of incident and reflected sound waves. Reflection occurs at the open or closed end of the tube. The positions of nodes and antinodes depend on the length of the tube and whether the ends are open or closed.

Ready to test yourself?

Practice with MCQ questions to check your understanding of Stationary waves.

Take Quiz
7.5 Polarisation 8.2 Diffraction