Waves Study Notes

Waves Overview

  • Waves are disturbances transferring energy through a medium or vacuum.

Types of Waves

  • Transverse Waves: Particle motion is perpendicular to wave direction (e.g., rope, light waves).
  • Longitudinal Waves: Particle motion is parallel to wave direction (e.g., sound waves).

Wave Properties

  • Wavelength (λ): Distance between successive similar points; measured in meters.
  • Displacement (x): Distance of a point from equilibrium; measured in meters.
  • Amplitude (A): Maximum displacement from equilibrium.
  • Period (T): Time for one complete oscillation; measured in seconds.
  • Frequency (f): Number of oscillations per second; measured in Hertz (Hz).
    • Relation: f = \frac{1}{T}.
  • Wave Speed (v): Rate of energy transfer or wave front propagation; v = \lambda f.

Classification of Waves

  • Mechanical Waves: Require medium (e.g., sound, water waves).
  • Electromagnetic Waves: Can travel in vacuum (e.g., radio waves, light).

Wave Behavior

  • Phase Difference: Variation in timing between wave points, measured in degrees or radians.
  • Intensity: Rate of energy transfer per unit area; I \propto (A^2)(f^2).

Doppler Effect

  • Change in frequency/wavelength due to relative motion between source and observer.
  • Source moving towards observer: Higher observed frequency.
  • Source moving away from observer: Lower observed frequency.

Polarization of Waves

  • Transverse waves can be polarized (restricted to one direction).
  • Longitudinal waves (e.g., sound) cannot be polarized.
    • Malus's Law: I = I_0 cos^2(\theta) for intensity after passing through polarizers.

Measuring Wave Properties

  • Use of cathode ray oscilloscope (C.R.O) to measure frequency/amplitude of sound waves.
    • Example Measurements: Time base (ms/cm), y-gain (mV/cm), amplitude, period, frequency calculations.