Wave Physics Lecture Notes

Vocabulary flashcards covering the fundamental concepts of waves, including wave types, properties, interference, standing waves, and wave behaviors like the Doppler Effect, refraction, and diffraction.

Wave

A disturbance or movement that transfers energy through a medium without any permanent displacement.

Medium

A substance through which waves travel.

Transverse Waves

Waves where matter moves up and down perpendicular to the direction of propagation (e.g., a rope).

Longitudinal Waves

Waves where matter moves back and forth in the same direction of propagation.

Mechanical Waves

Waves that require a medium in order to transport their energy.

Electromagnetic Waves

Waves that can travel through a vacuum and do not require a medium.

Amplitude

A wave feature where the larger the value, the greater the energy transported by the wave.

Period ($T$)

The time for a full wavelength to pass a position, calculated as $T = \frac{1}{f}$.

Frequency ($f$)

The number of wavelengths passing a position in one second, measured in Hertz ($Hz$).

Wave Speed ($v$)

The speed of a wave calculated by frequency times wavelength ($v = f \times \text{lambda}$).

Wavelength ($\text{lambda}$)

The distance of one wave cycle, measured in meters ($m$) and represented by the Greek letter $\text{lambda}$; its symbol is \text{\lambda}.

Principle of Superposition

The rule stating that two separate waves in a medium add up.

Constructive Interference

When two crests overlap, resulting in an increased amplitude.

Destructive Interference

When a crest and trough overlap, resulting in a decreased amplitude.

Nodes

Positions in a standing wave where the wave does not vibrate.

Anti-nodes

Positions in a standing wave where the wave vibrates with the maximum amplitude.

Standing Wave Harmonics (Type A and B)

For waves with two ends fixed or two ends free, where wavelength is $\text{lambda}_n = \frac{2L}{n}$ and frequency is $f_n = nf_1$.

Standing Wave Harmonics (Type C)

For waves with one end fixed and one end free, where wavelength matches the formula $\text{lambda}_n = \frac{4L}{2n - 1}$.

Beats

An alternating constructive and destructive interference caused by playing two sound waves of unequal but close frequencies, causing the sound to alternate between loud and soft.

Doppler Effect

The phenomenon where a source moving toward an observer creates a shorter wavelength and higher frequency, while moving away creates a longer wavelength and lower frequency.

Ray

A straight line with an arrow pointing in the direction the wave is travelling.

Wave Fronts

Lines or curves representing corresponding points on a wave that vibrate in unison, or in phase.

Law of Reflection

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

Refraction

The change in direction of a wave at the boundary between two different media.

Diffraction

The spreading of waves around the edge of a barrier or bending around a corner.