Waves - General properties of waves

Waves are oscillations that transfer energy and information from one place to another without the transfer of matter.

Transverse Waves: The vibrations are perpendicular ($90^{\circ}$) to the direction of energy transfer. Examples include electromagnetic waves (light, radio) and water ripples.

Longitudinal Waves: The vibrations are parallel to the direction of energy transfer. These consist of compressions (high pressure) and rarefactions (low pressure). Example: Sound waves.

Amplitude ($A$): The maximum displacement of a point on a wave away from its undisturbed (rest) position.

Wavelength ($\lambda$): The distance from a point on one wave to the equivalent point on the adjacent wave (e.g., crest to crest or trough to trough).

Frequency ($f$): The number of waves passing a fixed point per second, measured in Hertz ($Hz$).

Period ($T$): The time taken for one complete wave to pass a fixed point, related to frequency by $T = \frac{1}{f}$.

Wavefront: An imaginary line that joins all adjacent points that are in phase (e.g., all the crests in a ripple tank).

Reflection: Occurs when a wave hits a boundary and bounces back. The law of reflection states the angle of incidence is equal to the angle of reflection ($i = r$).

Refraction: The change in direction of a wave when it transmits from one medium to another due to a change in speed. If a wave slows down, it bends towards the normal.

Diffraction: The spreading out of waves as they pass through a gap or around an edge. Diffraction is most significant when the gap size is approximately equal to the wavelength ($\lambda$).