Wave Properties: Energy Transfer and Wave Types

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

Waves Transfer Energy

• When traveling through a medium, wave particles oscillate and transfer energy.
• Particles stay in the same place with only energy being transferred.
• Ripples on water demonstrate this, as they don't carry water or a twig away.
• Sound waves from a guitar string do not carry air to create a vacuum.
• Amplitude is the maximum displacement of a wave from its undisturbed position.
• Wavelength is the distance between the same point on two adjacent waves.
• Frequency is the number of complete waves passing a point per second, measured in hertz (Hz) where 1 Hz equals 1 wave per second.
• Period determines the time for a full wave cycle.
• Waves can be either transverse or longitudinal.

Transverse Waves

• Oscillations (vibrations) are perpendicular (at 90°) to the direction of energy transfer.
• Most waves are transverse, with examples including electromagnetic waves, ripples and water waves, and waves on a string.

Longitudinal Waves

• Oscillations are parallel to the direction of energy transfer.
• Sound waves in air serve as an example.

Wave Speed

• The speed at which energy is transferred (or the speed at which the wave moves).
• Wave equation applies to all waves.
• Wave speed = Frequency x Wavelength, where wave speed is in m/s, frequency in Hz, and wavelength in meters.

Example

• To find the wavelength for a radio wave with a frequency of 12.0 x 10^9 Hz, given that radio waves travel at 3.0 x 10^8 m/s in the air, the wavelength is λ = v / f = (3.0 x 10^8) / (12.0 x 10^9) = 0.025 m