Fundamentals of Wave Motion and Physics Phenomena

1. Wave Motion

Features:

• ¹Transmit power
• ²No transport of matter
• ³Particles vibrate about an equilibrium point

Types of Waves

According to the propagation medium

• Mechanical: Need an elastic medium for propagation.
• Electromagnetic: Do not require a medium.

According to the direction of propagation

• Longitudinal: Vibrations of the particles follow the direction of the waves (e.g., sound).
• Transverse: Vibrations follow a direction perpendicular to the waves (e.g., ripples on water).

2. Wave Propagation

Waves spread via sinusoidal functions (sine and cosine).

• Pulse: An isolated wave.
• Train: Successive waves.

3. Characteristics of Waves

• Velocity of Propagation (V): Distance traveled by the wave per second (m/s).
• Wavelength (λ): Distance between two successive points of the wave that vibrate in the same way (distance between crests) (m).
• Period (T): Time the wave takes to travel one wavelength (s).
• Frequency (f): Number of waves or vibrations per second (Hz). This is the inverse of the period (f = 1/T).
• Amplitude (A): Maximum separation from the equilibrium position (m).
• Wave Intensity (I): Amount of energy flowing through the medium per unit area and time (W/m² or J/m²·s). Calculated as I = E / (S · T).

4. Wave Phenomena

1. Wave Reflection

Definition: The change of direction experienced by a wave train upon colliding with a smooth surface without crossing it. The ray is parallel to the wave front.

Laws:

• The incident ray, the reflected ray, and the normal lie in the same plane.
• The angle of incidence equals the angle of reflection.
• The wave speed remains unchanged.

2. Refraction of Waves

Definition: Change of speed experienced by a wave train due to a change in medium density or depth.

Laws:

• The incident ray, the refracted ray, and the normal lie in the same plane.
• If the beam passes into a denser medium, the refracted ray approaches the normal.
• If the beam passes into a less dense medium, the refracted ray moves away from the normal.
• If the beam does not coincide with the normal, it deviates.

3. Diffraction of Waves

Definition: The phenomenon that occurs when a wave changes its propagation direction after encountering an opening.

Key Relationship: Velocity (V) = Wavelength (λ) / Period (T)