Wave Propagation and Properties

Wave Propagation

• Waves are disturbances or vibrations that travel from one place to another, carrying energy.

• Examples of wave propagation include water ripples, sound waves, seismic waves, and electromagnetic waves.

Wave Properties

• All waves have frequency (number of waves per unit time), amplitude (maximum displacement), and wavelength (distance between successive crests/troughs).

• Frequency and wavelength are inversely related; higher frequency means shorter wavelength.

• Wave speed (v) is calculated as: v = fλ (where f is frequency and λ is wavelength).

• Electromagnetic waves travel at a constant speed of 3.0 × 10⁸ m/s in a vacuum. Sound waves travel at approximately 343 m/s in dry air at 20°C.

Wave Medium

• Mechanical waves (like water waves, sound waves, and string waves) require a medium to travel through.

• Electromagnetic waves (like light, radio waves) do not need a medium. They can travel through a vacuum.

• Wave speed in a medium is affected by the properties of the medium (e.g., density, tension).

Factors Affecting Wave Speed

• Mechanical waves (e.g., waves in a string): Tension and mass per unit length affect speed. Higher tension means faster speed, higher mass (per length) means slower speed.

• Sound waves: Rigidity and density of the medium affect speed. More rigid materials mean faster sound, and denser materials mean slower sound. Temperature also affects speed - higher temperature means faster sound.

Wave Types

• Transverse waves: Particle vibration is perpendicular to wave propagation. Examples include light waves, electromagnetic waves, and S-waves.

• Longitudinal waves: Particle vibration is parallel to wave propagation. Examples include sound waves, and P-waves (a type of seismic wave).