Oscillations & Waves Vocabulary

Vocabulary flashcards covering wave characteristics, properties, interference, standing waves, and damping concepts from Physics lecture notes.

Pulse

A single disturbance that transfers energy over a distance.

Oscillation

A periodic (regularly repeating) disturbance.

Wave

A periodic disturbance that transfers energy over a distance without any net transfer of the medium.

Mechanical Waves

Waves (e.g., sound, water waves) that require a medium to propagate through.

Electromagnetic Waves

Transverse waves consisting of a varying electric field and varying magnetic field at right angles to each other that do not require a medium to propagate and travel at $c = 3.00 \times 10^8\,\text{m}\cdot\text{s}^{-1}$ in a vacuum.

Transverse Wave

A wave in which the particles oscillate at right angles ($90^\circ$) to the direction of travel.

Longitudinal Wave

A wave in which the particles oscillate along the direction of travel.

Crest

The point of maximum amplitude in a transverse wave.

Trough

The point of minimum amplitude in a transverse wave.

Compression

The point in a longitudinal wave where the particles are closest together.

Rarefaction

The point in a longitudinal wave where the particles are farthest apart.

Ray

An arrow showing the direction in which a wave is propagating.

Wavefronts

Lines showing the wave crests looking down on the waves from above.

Displacement ($x$)

How far a particle has moved from its rest position, measured in meters ($\text{m}$).

Wavelength ($\lambda$)

The distance between two consecutive particles that have the same displacement, such as consecutive crests/compressions or troughs/rarefactions.

Frequency ($f$)

The number of wavelengths that pass a given point every second, measured in hertz ($\text{Hz}$) or $\text{s}^{-1}$.

Period ($T$)

The amount of time taken for one wavelength to pass a given point ($T = \frac{1}{f}$).

Amplitude ($A$)

The maximum displacement of a particle from its rest position.

Intensity ($I$)

The energy that a wave transports per unit time across a unit area of the medium ($I \propto A^2$).

Displacement-Position Graph

A graph showing a snapshot of a wave across space at a given time.

Displacement-Time Graph

A graph showing how the displacement of one specific particle in the medium varies over time.

First Law of Reflection

The law stating that the angle of incidence equals the angle of reflection ($\theta_i = \theta_r$).

Second Law of Reflection

The law stating that the incident ray, normal line, and reflected ray all lie on the same plane.

Refraction

The bending of waves as they travel from one medium to another due to a change in wave speed.

Refractive Index ($n$)

A relative scale without units that relates to how fast waves travel through a medium.

Snell’s Law

A formula relating the angle of incidence, angle of refraction, and refractive indices of two media: $n_1 \sin(\theta_1) = n_2 \sin(\theta_2)$.

Huygens’ Principle

Every point on a wavefront can be considered as a source of tiny wavelets spreading out in the forward direction at the speed of the wave, forming a new wavefront tangent to the wavelets.

Diffraction

The slight bending of waves when travelling past an obstacle or through an aperture.

Principle of Superposition

When two waves of the same nature travel past each other simultaneously, the resultant displacement is the sum of the displacements of the individual waves.

Constructive Interference

Interference that occurs when displacements of individual waves are in the same direction, resulting in a wave with a greater amplitude.

Destructive Interference

Interference that occurs when displacements of individual waves are in opposite directions, resulting in a wave with a lesser amplitude.

Antinode

A point where constructive interference occurs, resulting in maximum displacement.

Node

A point where destructive interference occurs, resulting in zero displacement.

Beat Frequency

The periodic oscillation in the amplitude of a combined waveform caused by the interference of two waves of slightly different frequencies.

Natural Frequency

The inherent rate at which a system vibrates when disturbed and left alone, determined solely by physical properties like mass, stiffness, and shape.

Resonant Frequency

The specific frequency of an external driving force that causes a system to vibrate with maximum amplitude.

Damping

The reduction in amplitude of oscillations over time due to friction forces dissipating energy as heat.

Lightly Damped System

An oscillating system in which the amplitude decays very gradually.

Heavily Damped System

An oscillating system in which the amplitude decays rapidly.

Critically Damped System

A system damped so heavily that the object comes to rest at the equilibrium position without oscillating.

Resonance Curve

A plot of oscillation amplitude against driver frequency, showing a peak when the driver frequency matches the natural or resonant frequency.