Waves and sound - physics 2

Wave

A traveling disturbance that carries energy from place to place without the bulk movement of matter.

Transverse Wave

A wave in which the disturbance moves perpendicular to the direction of the wave's energy.

Longitudinal Wave

A wave in which the disturbance moves parallel to the direction of the wave's energy.

Combination Waves

Waves (like water waves) that are partially transverse and partially longitudinal.

Periodic Wave

A wave whose disturbance pattern repeats exactly over an extended length of time.

Wavelength (λ)

The horizontal length of one complete wave cycle (Unit: meters).

Period (T)

The time required for one complete wave cycle to pass a point (Unit: seconds).

Frequency (f)

The number of wave cycles completed in one second (Unit: s⁻¹ or Hz).

Frequency Formula

f = 1 / T

Amplitude (A)

The maximum range of a wave's disturbance measured from its undisturbed position.

Peak to Peak Amplitude (Ap

p)

Wave Speed Formula

v = f * λ (or v = λ / T)

Nature of Sound Waves

Longitudinal waves made of a series of compressions (condensations) and rarefactions through a medium.

Sound Intensity (I)

The power (P) passing perpendicularly through a surface divided by its area (A). Unit: W/m².

Sound Intensity Formula

I = P / A

Uniform Sound Intensity vs Distance

I = P / (4 * π * r²)

Threshold of Hearing

The smallest sound intensity a human ear can detect for a 1000 Hz tone (1.00 x 10⁻¹² W/m²).

Decibel (dB)

A logarithmic measurement unit used to compare the intensity levels (loudness) of two sound waves.

Intensity Level Formula (β)

β = (10 dB) * log(I / I₀)

Pitch

The brain's psychological interpretation of a sound wave's frequency.

Pure Tone

A sound wave that consists of a simple, single

Quality or Timbre

The unique character of a sound created by a mixture of a fundamental frequency and overtones.