(455) Properties of waves [IB Physics SL/HL]

Properties of Waves

• Waves have distinct properties that can be measured and calculated.

Wave Equation

• Equation: V = Fλ

  • V: Speed of the wave (measured in m/s)

  • F: Frequency (measured in Hertz or Hz, 1/s)

  • λ (lambda): Wavelength (measured in meters)

• Frequency Context:

  • Measured in Hertz (cycles per second)

  • Example: Computer speed measured in gigahertz (billions of calculations/second)

Graphical Features of Waves

• There are different types of graphs for displacement vs. position and displacement vs. time:

  • Displacement vs. Position Graph:

    • Amplitude: Distance from the middle of the wave to the peak (measured in meters)

    • Wavelength (λ): Distance from peak to peak or trough to trough (also measured in meters)

  • Displacement vs. Time Graph:

    • Period: Time taken for one full cycle (measured in seconds)

    • Amplitude remains the same as in position graphs.

Particle Motion and Wave Movement

• The particle's motion remains fixed in position when measuring displacement.

  • As the wave passes, the particle moves up and down but does not move left or right.

• Typical exam question might involve determining the particle's motion based on wave direction.

Frequency Relation

• Frequency Equation: f = 1/T

  • T: Period of the wave (measured in seconds)

  • Frequency (f) is the inverse of period, measured in Hz or 1/s.

Types of Waves

• Transverse Waves:

  • Oscillation perpendicular to wave travel direction (e.g., water waves, light waves).

• Longitudinal Waves:

  • Oscillation parallel to wave travel direction (e.g., sound waves).

  • Requires a medium (e.g., air molecules) to transmit the wave.

Important Notes

• Sound cannot travel in space due to lack of medium; light waves can travel through a vacuum.