8.1.2
Stationary Waves 2
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Stationary Wave Practical
This practical investigates how the frequency of stationary waves on a string changes when length, tension and mass per unit length are changed.

Initial measurements
- Measure the length of the string, the tension in the string and the mass per unit length.
- The tension can be calculated by multiplying the total mass of the masses and the acceleration due to gravity.
- The mass per unit length can be calculated by dividing the total mass of the string by its length.

Determine frequency of first harmonic
- This can be found by varying the frequency until you see the pattern needed for the first harmonic.
- Two nodes at each end of the string with one antinode in the centre.

Change variable - length
- To investigate how changing the length affects the resonant frequency, keep the tension and mass per unit length the same.
- Vary the length of the string by moving the oscillator away or toward the pulley.
- At each string length, find the new first harmonic.
- Plot a graph of f against l.

Change variable - mass per unit length
- To investigate how changing μ affects the resonant frequency, keep the tension and length the same.
- Vary μ by using different types of material for the string.
- For each material (with a different value of μ), find the new first harmonic.
- Plot a graph of μ against f.

Change variable - tension
- To investigate how changing tension affects the resonant frequency, keep the length and mass per unit length the same.
- Vary the tension in the string by varying the mass attached to the end.
- At each value of tension, find the new first harmonic.
- Plot a graph of f against T.
Stationary Wave Practical - Results
The frequency of the first harmonic of a string can be calculated using an equation. The practical shown previously should show certain relationships.

First harmonic equation
- We expect that the frequency of the first harmonic should be given by:

Relationship with length
- The longer the length of the string, the lower the frequency.
- This is because the longer the length is, the longer the half wavelength must be, and so the lower the frequency.

Relationship with μ
- The larger the mass per unit length, μ, the lower the resonant frequency.
- For the same length string, waves travel more slowly through a heavier string, so the frequency must be lower.
- Remember

Relationship with tension
- The higher the tension in the string, the higher the frequency.
- This is because waves travel more quickly down a string with higher tension.
1Physical Quantities & Units
1.1Physical Quantities & Units
2Kinematics
3Dynamics
3.1Momentum & Newton's Laws of Motion
3.2Non-Uniform Motion
3.3Linear Momentum & Conservation
4Force, Density & Pressure
4.1Force, Density & Pressure
4.1.1Fields4.1.2Force in Uniform Fields4.1.3Friction4.1.4Buoyancy4.1.5Terminal Speed4.1.6End of Topic Test - Acceleration Due to Gravity4.1.7Centre of Mass4.1.8Forces & Equilibrium4.1.9End of Topic Test - Scalars & Vectors4.1.10Moments4.1.11End of Topic Test - Moments & Centre of Mass4.1.12Density4.1.13Pressure
5Work, Energy & Power
6Deformation of Solids
7Waves
7.1Simple Harmonic Motion
7.2Waves
7.2.1Progressive Waves7.2.2Intensity of Waves7.2.3Wave Speed & Phase Difference7.2.4Longitudinal & Transverse Waves7.2.5End of Topic Test - Progressive Waves7.2.6Electromagnetic Waves7.2.7Doppler Effect7.2.8Sound Waves7.2.9Measuring Sound Waves7.2.10End of Topic Test - Waves7.2.11Ultrasound Imaging7.2.12Ultrasound Imaging 2
8Superposition
9Thermal Physics
9.1Circular Motion
9.2Thermal Physics
9.2.1Temperature9.2.2Measuring Temperature9.2.3Ideal Gas Law9.2.4Ideal Gases9.2.5Boyle's Law & Charles' Law9.2.6Molecular Kinetic Theory Model9.2.7Molecular Kinetic Theory Model 29.2.8Thermal Energy Transfer9.2.9Thermal Energy Transfer Experiments9.2.10End of Topic Test - Thermal Energy & Ideal Gases9.2.11First Law of Thermodynamics
10Communication
10.1Communication Channels
10.2Digital Communication
11Electric Fields
11.1Electric Fields
12Current Electricity
12.1Current Electricity
12.1.1Basics of Electricity12.1.2Mean Drift Velocity12.1.3Current-Voltage Characteristics12.1.4End of Topic Test - Basics of Electricity12.1.5Resistivity12.1.6End of Topic Test - Resistivity & Superconductors12.1.7Power and Conservation12.1.8Microphones12.1.9Components12.1.10Relays12.1.11Strain Gauges
13Magnetic Fields
13.1Magnetic Fields
14Modern Physics
14.1Quantum Physics
14.1.1The Photoelectric Effect14.1.2The Photoelectric Effect Explanation14.1.3End of Topic Test - The Photoelectric Effect14.1.4Collisions of Electrons with Atoms14.1.5Energy Levels & Photon Emission14.1.6Wave-Particle Duality14.1.7End of Topic Test - Absorption & Emission14.1.8Band Theory14.1.9Diagnostic X-Rays14.1.10X-Ray Image Processing14.1.11Absorption of X-Rays14.1.12CT Scanners
14.2Nuclear Physics
14.2.1Rutherford Scattering14.2.2Atomic Model14.2.3Isotopes14.2.4Stable & Unstable Nuclei14.2.5A-A* (AO3/4) - Stable & Unstable Nuclei14.2.6Alpha & Beta Radiation14.2.7Gamma Radiation14.2.8Particles, Antiparticles & Photons14.2.9Quarks & Antiquarks14.2.10Particle Interactions14.2.11Radioactive Decay14.2.12Half Life14.2.13End of Topic Test - Radioactivity14.2.14Nuclear Instability14.2.15Mass & Energy14.2.16Binding Energy14.2.17A-A* (AO3/4) - Nuclear Fusion
Jump to other topics
1Physical Quantities & Units
1.1Physical Quantities & Units
2Kinematics
3Dynamics
3.1Momentum & Newton's Laws of Motion
3.2Non-Uniform Motion
3.3Linear Momentum & Conservation
4Force, Density & Pressure
4.1Force, Density & Pressure
4.1.1Fields4.1.2Force in Uniform Fields4.1.3Friction4.1.4Buoyancy4.1.5Terminal Speed4.1.6End of Topic Test - Acceleration Due to Gravity4.1.7Centre of Mass4.1.8Forces & Equilibrium4.1.9End of Topic Test - Scalars & Vectors4.1.10Moments4.1.11End of Topic Test - Moments & Centre of Mass4.1.12Density4.1.13Pressure
5Work, Energy & Power
6Deformation of Solids
7Waves
7.1Simple Harmonic Motion
7.2Waves
7.2.1Progressive Waves7.2.2Intensity of Waves7.2.3Wave Speed & Phase Difference7.2.4Longitudinal & Transverse Waves7.2.5End of Topic Test - Progressive Waves7.2.6Electromagnetic Waves7.2.7Doppler Effect7.2.8Sound Waves7.2.9Measuring Sound Waves7.2.10End of Topic Test - Waves7.2.11Ultrasound Imaging7.2.12Ultrasound Imaging 2
8Superposition
9Thermal Physics
9.1Circular Motion
9.2Thermal Physics
9.2.1Temperature9.2.2Measuring Temperature9.2.3Ideal Gas Law9.2.4Ideal Gases9.2.5Boyle's Law & Charles' Law9.2.6Molecular Kinetic Theory Model9.2.7Molecular Kinetic Theory Model 29.2.8Thermal Energy Transfer9.2.9Thermal Energy Transfer Experiments9.2.10End of Topic Test - Thermal Energy & Ideal Gases9.2.11First Law of Thermodynamics
10Communication
10.1Communication Channels
10.2Digital Communication
11Electric Fields
11.1Electric Fields
12Current Electricity
12.1Current Electricity
12.1.1Basics of Electricity12.1.2Mean Drift Velocity12.1.3Current-Voltage Characteristics12.1.4End of Topic Test - Basics of Electricity12.1.5Resistivity12.1.6End of Topic Test - Resistivity & Superconductors12.1.7Power and Conservation12.1.8Microphones12.1.9Components12.1.10Relays12.1.11Strain Gauges
13Magnetic Fields
13.1Magnetic Fields
14Modern Physics
14.1Quantum Physics
14.1.1The Photoelectric Effect14.1.2The Photoelectric Effect Explanation14.1.3End of Topic Test - The Photoelectric Effect14.1.4Collisions of Electrons with Atoms14.1.5Energy Levels & Photon Emission14.1.6Wave-Particle Duality14.1.7End of Topic Test - Absorption & Emission14.1.8Band Theory14.1.9Diagnostic X-Rays14.1.10X-Ray Image Processing14.1.11Absorption of X-Rays14.1.12CT Scanners
14.2Nuclear Physics
14.2.1Rutherford Scattering14.2.2Atomic Model14.2.3Isotopes14.2.4Stable & Unstable Nuclei14.2.5A-A* (AO3/4) - Stable & Unstable Nuclei14.2.6Alpha & Beta Radiation14.2.7Gamma Radiation14.2.8Particles, Antiparticles & Photons14.2.9Quarks & Antiquarks14.2.10Particle Interactions14.2.11Radioactive Decay14.2.12Half Life14.2.13End of Topic Test - Radioactivity14.2.14Nuclear Instability14.2.15Mass & Energy14.2.16Binding Energy14.2.17A-A* (AO3/4) - Nuclear Fusion
Practice questions on Stationary Waves 2
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- 2How do you find the mass per unit length of the string?Multiple choice
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