GCSE Physics - Intro to Waves - Longitudinal and Transverse Waves #61

Basics of Waves

• Waves transfer energy from one place to another without transferring matter.

  • Example: Light waves from a phone screen to your eye, sound waves from speakers to your ear.

  • Energy can represent meaningful information, such as images and tunes.

Wave Properties

• Waves oscillate or vibrate as they travel.

  • Displacement-distance graph shows:

    • Distance: how far the wave has traveled.

    • Displacement: how far the wave moves from its equilibrium point (up or down).

    • Amplitude: maximum displacement from equilibrium.

    • Wavelength: distance of one entire oscillation (crest to crest or trough to trough).

    • Crest: top of the wave; Trough: bottom of the wave.

Displacement-Time Graph

• Shows time on the x-axis:

  • One complete oscillation is measured as the time period.

  • Time Period: time taken for one complete oscillation.

  • Frequency (in hertz): number of complete oscillations per second.

Frequency Calculation

• Frequency (f) can be calculated using:

  • f = 1 / Time Period

• Example: If the time period is 0.5 seconds, frequency is f = 1 / 0.5 = 2 Hz.

Wave Speed Calculation

• Wave Speed (v) is calculated by:

  • v = Wavelength (λ) x Frequency (f).

• Example:**

  • Sound wave with frequency of 400 Hz and wavelength of 70 cm (0.7 m):

  • Wave Speed = 0.7 m x 400 Hz = 280 m/s.

Types of Waves

Transverse Waves

• Oscillations are perpendicular to the direction of energy transfer:

  • Example: Light waves, radio waves, water waves, waves on a string (e.g., guitar).

Longitudinal Waves

• Oscillations are parallel to the direction of energy transfer:

  • Regions of compression (more dense) and rarefaction (less dense).

  • Example: Sound waves, seismic P-waves.

Conclusion

• Understanding these fundamentals will help in grasping more complex wave behaviors.