Wave Properties Flashcards

Wave Basics

Energy Transfer

• Waves transfer energy from one place to another without transferring matter.
  • Example: Light waves from a phone screen to the eye, sound waves from speakers to the ear.
  • Energy can be interpreted as meaningful information by the brain to build up images and tunes.

Wave Properties

• Waves vibrate or oscillate as they travel.
• Displacement-Distance Graph:
  • Distance: How far the wave has traveled from the starting point.
  • Displacement: How far from the equilibrium point the wave has oscillated (up or down).
  • Amplitude: The maximum displacement from the equilibrium point.
  • Wavelength: The distance of one complete oscillation.
    • Can be measured from equilibrium, up, down, and back up.
    • Also measured from crest to crest (or trough to trough).
    • Crest: The very top of a wave.
    • Trough: The opposite of the crest (the very bottom of a wave).

Displacement-Time Graph

• X-axis represents time instead of distance.
• The length of one complete oscillation represents the time period (T).
  • Time Period (T): The time it takes for one complete oscillation.
• Frequency (f): The number of complete oscillations per second, measured in Hertz (Hz).
  • f = \frac{1}{T}
  • T = \frac{1}{f}
  • Example:
    • If each oscillation takes 0.5 seconds (T = 0.5 s), then the frequency is 2 Hz (two oscillations per second).
    • If the frequency of a wave is 4 Hz, then the time period is 0.25 seconds per oscillation.

Wave Speed

• Wave speed (v) is calculated by multiplying the wavelength ((\lambda)) by the frequency (f).
  • v = \lambda f
  • Example: Sound wave with a frequency of 400 Hz and a wavelength of 70 cm.
    • Convert 70 cm to 0.7 meters.
    • v = 0.7 \, \text{m} \times 400 \, \text{Hz} = 280 \, \text{m/s}

Types of Waves

Transverse Waves

• Oscillations are perpendicular to the direction of energy transfer.
  • Vibrations go up and down while the wave travels horizontally.
• Examples:
  • Electromagnetic waves (light, radio waves).
  • Ripples and waves in water.
  • Waves on a string (e.g., guitar string).

Longitudinal Waves

• Oscillations are parallel to the direction of energy transfer.
• Leads to regions of compression and rarefaction (more spread out).
• Area of compression moves from left to right within the wave.
• Examples:
  • Sound waves.
  • Some types of shock waves (e.g., seismic P-waves).