3.5.1
Standing Waves
Stationary Waves
Stationary Waves
Stationary waves are important physical concepts. They can be created when a wave interferes with its reflection.


Definition
Definition
- A stationary wave is formed when two progressive waves, each with the same frequency and wavelength and moving in opposite directions, interfere with one another.
- This creates a wave which doesn't transfer energy from one place to another.


Nodes
Nodes
- Nodes are points on a stationary wave that have zero amplitude.
- Having zero amplitude means that they are stationary.


Antinodes
Antinodes
- Antinodes are points on a stationary wave with maximum amplitude.
- They oscillate from the furthest point upwards to the furthest point downwards.
Resonance and Harmonics
Resonance and Harmonics
Stationary waves can only have certain frequencies. These frequencies are called resonant frequencies. Each resonant frequency is called a harmonic.


Resonance - first harmonic
Resonance - first harmonic
- Stationary waves can only happen at resonant frequencies.
- Resonant frequencies happen when the distance between the two fixed ends is an integer multiple of half wavelengths, ½λ.
- The first resonant frequency is called the first harmonic.
- It happens when the distance between the two fixed ends is exactly ½λ.
- The first harmonic is shown in the diagram.
- It has two nodes and one antinode.
- The first harmonic is also known as the fundamental.


Second harmonic
Second harmonic
- The second resonant frequency is called the second harmonic.
- It happens when the distance between the two fixed ends is exactly λ.
- It contains two ½λ lengths.
- The second harmonic has a frequency twice as big as the first harmonic.
- It has three nodes and two antinodes.


Third harmonic
Third harmonic
- The third resonant frequency is called the third harmonic.
- It happens when the distance between the two fixed ends is exactly 1½λ.
- It contains three ½λ lengths.
- The third harmonic has a frequency three times as big as the first harmonic.
- It has four nodes and three antinodes.
1Space, Time & Motion
1.1Motion
1.2Forces
1.3Momentum & Impulse
2The Particulate Nature of Matter
2.1Thermal Concepts
3Wave Behaviour
3.1Oscillations
3.2Travelling Waves
3.3Wave Characteristics
3.4Wave Behaviour
3.5Standing Waves
3.6Simple Harmonic Motion
3.7Single Slit Diffraction
3.8Interference
3.9Doppler Effect
4Fields
4.1Circular Motion
4.2Newton's Law of Gravitation
4.3Fields
4.4Fields at Work
4.5Electric Fields
4.6Magnetic Effect of Electric Currents
4.7Heating Effect of Currents
4.8Electromagnetic Induction
4.9Power Generation & Transmission
5Nuclear & Quantum Physics
5.1Discrete Energy & Radioactivity
5.2Nuclear Reactions
5.3The Interaction of Matter with Radiation
6Measurements
6.1Measurements & Errors
6.2Uncertainties & Errors
6.3Vectors & Scalars
Jump to other topics
1Space, Time & Motion
1.1Motion
1.2Forces
1.3Momentum & Impulse
2The Particulate Nature of Matter
2.1Thermal Concepts
3Wave Behaviour
3.1Oscillations
3.2Travelling Waves
3.3Wave Characteristics
3.4Wave Behaviour
3.5Standing Waves
3.6Simple Harmonic Motion
3.7Single Slit Diffraction
3.8Interference
3.9Doppler Effect
4Fields
4.1Circular Motion
4.2Newton's Law of Gravitation
4.3Fields
4.4Fields at Work
4.5Electric Fields
4.6Magnetic Effect of Electric Currents
4.7Heating Effect of Currents
4.8Electromagnetic Induction
4.9Power Generation & Transmission
5Nuclear & Quantum Physics
5.1Discrete Energy & Radioactivity
5.2Nuclear Reactions
5.3The Interaction of Matter with Radiation
6Measurements
6.1Measurements & Errors
6.2Uncertainties & Errors
6.3Vectors & Scalars
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