physics waves better

Transverse Wave

A wave in which the particles of the medium oscillate perpendicular to the direction of energy propagation. /

Longitudinal Wave

A wave in which the particles of the medium oscillate parallel to the direction of energy propagation. /

Wavefront

An imaginary line or surface connecting adjacent points of a wave that are vibrating in phase. /

Phase Difference

The difference in position or timing between two points in a wave cycle, measured in radians or degrees. /

In Phase

Points on a wave or two waves that are at the exact same stage in their cycle, having zero phase difference. /

Out of Phase

Points on a wave or two waves that are at different stages in their cycle, producing destructive interference if completely opposed ($180^\circ$ or $\pi$ radians). /

Superposition

The principle stating that when two or more waves overlap, the resultant displacement is the vector sum of individual displacements. /

Constructive Interference

The superposition of two waves arriving in phase, resulting in a wave with greater amplitude. /

Destructive Interference

The superposition of two waves arriving out of phase, resulting in a wave with reduced or zero amplitude. /

Path Difference

The difference in distance traveled by two waves from their respective sources to a point of intersection. /

Central Antinode

The central maximum in an interference pattern where waves travel equal distances and arrive in phase ($\Delta s = 0$). /

Nodal Line

A line along an interference pattern connecting points of continuous destructive interference where path difference is an odd half-wavelength. /

Antinodal Line

A line along an interference pattern connecting points of continuous constructive interference where path difference is a whole number of wavelengths. /

Monochromatic Light

Light consisting of a single frequency or wavelength. /

Coherent Sources

Wave sources that emit waves with identical frequency, wavelength, and a constant phase difference. /

Two-Slit Interference

An interference pattern created by light passing through two narrow slits acting as coherent sources

Diffraction Grating

A plate containing thousands of closely spaced parallel lines that scatters light into sharp, widely spaced interference maxima

Grating Spacing ($d$)

The physical distance between adjacent lines or slits on a diffraction grating, equal to the reciprocal of lines per metre. /

Single-Slit Diffraction

The spreading of light through a single narrow aperture creating a central bright maximum flanked by darker minima where $a\sin\theta = n\lambda$. /

Diffraction

The spreading of waves around obstacles or through narrow gaps, which is most pronounced when the gap width is comparable to the wavelength. /

Thin Film Interference

Interference produced by light reflecting off the top and bottom boundaries of a thin layer of transparent medium. /

Phase Inversion

A half-wavelength ($\pi$ radian) phase shift that occurs when a wave reflects off a medium with a higher refractive index. /

Optical Path Length

The distance a light wave travels scaled by the refractive index of the medium through which it moves ($OPL = n \times d$). /

Standing Wave

A wave pattern formed by the superposition of two identical waves traveling in opposite directions, characterized by fixed nodes and antinodes. /

Node

A point along a standing wave where destructive interference causes zero displacement at all times. /

Antinode

A point along a standing wave where constructive interference creates maximum oscillation amplitude. /

Fundamental Frequency

The lowest frequency at which a system produces a standing wave, also known as the first harmonic. /

Harmonic

An integer multiple of the fundamental frequency produced by a resonant system. /

Overtone

Any resonant frequency above the fundamental frequency produced by a vibrating body. /

Closed Pipe Resonance

Standing sound waves in a pipe closed at one end, forming a node at the closed end, an antinode at the open end, and producing only odd harmonics. /

Open Pipe Resonance

Standing sound waves in a pipe open at both ends, forming antinodes at both ends and producing all integer harmonics. /

End Correction

A small distance added to the physical length of an open tube to account for the antinode extending slightly beyond the open end. /

Fundamental Wavelength of String

The longest wavelength for a standing wave on a fixed string of length $L$, equal to $2L$. /

Fundamental Wavelength of Closed Pipe

The longest wavelength for a standing wave in a pipe of length $L$ closed at one end, equal to $4L$. /

Wave Speed on a String

The speed of a transverse wave on a string, determined by tension and mass per unit length ($v = \sqrt{\frac{T}{\mu}}$). /

Doppler Effect

The apparent change in frequency of a wave caused by relative motion between the source and the observer. /

Apparent Frequency (Approaching Source)

The higher frequency observed when a wave source moves toward a stationary observer

Apparent Frequency (Receding Source)

The lower frequency observed when a wave source moves away from a stationary observer

Doppler Shift ($\Delta f$)

The absolute difference between the emitted frequency and the observed frequency due to relative motion. /

Compressed Wavelengths

The shortened distance between wavefronts in front of a moving wave source. /

Expanded Wavelengths

The lengthened distance between wavefronts behind a moving wave source. /

Beats

Periodic variations in loudness produced by the superposition of two sound waves of slightly different frequencies. /

Beat Frequency

The rate of volume pulsation equal to the absolute difference between two interfering frequencies ($f_{beat} = \vert{}f_1 - f_2\vert{}$). /

Refraction

The change in direction and speed of a wave as it passes from one medium into another of different density. /

Refractive Index ($n$)

A dimensionless ratio comparing the speed of light in a vacuum to the speed of light in a given medium ($n = \frac{c}{v}$). /

Critical Angle

The minimum angle of incidence at which light traveling from a denser to a rarer medium undergoes total internal reflection. /

Total Internal Reflection

Complete reflection of a light ray back into its original denser medium when the angle of incidence exceeds the critical angle. /

Polarisation

The process of restricting the electric field vibrations of a transverse wave to a single plane. /

Dispersion

The separation of white light into its component colors when passing through a medium due to different wavelengths traveling at slightly different speeds. /

Rayleigh Scattering

The scattering of light off particles smaller than its wavelength, causing shorter blue wavelengths to scatter more than longer red ones.