11.sound Flashcards
Longitudinal Waves
Direction: Particles vibrate parallel to the wave’s propagation.
Examples:
Sound waves
Seismic P-waves
Medium: Requires a medium (solid, liquid, or gas).
Key Feature: Compression and rarefaction.
Transverse Waves
Direction: Particles vibrate perpendicular to the wave’s propagation.
Examples:
Water surface waves
Seismic S-waves
Medium: Can travel in solids or at surfaces (e.g., water).
Key Feature: Crests and troughs.
Wavelength
The distance between two consecutive
compressions (C) or two consecutive
rarefactions (R) is called the wavelength
The wavelength is
usually represented by λ (Greek letter
lambda). Its SI unit is metre (m).
Frequency
Frequency is the number of complete oscillations or cycles of a wave that occur in a unit of time, typically measured in hertz (Hz). One hertz equals one cycle per second.
pitch
How the brain interprets the frequency
of an emitted sound is called its pitch
The loudness or softness of a sound is
determined basically by its
amplitute
amplitude
The magnitude of the maximum
disturbance in the medium on either side of
the mean value is called the amplitude of the
wave
the speed of sound in air is 331
m s–1 at 0ºCd 344 m s–1 at 22 ºC
speed of sound —— from solid to gas
decrease
The speed of sound in a medium depends on
temperature and medium
speed of sound ____with temperature
increase
To hear a distinct echo the time interval
between the original sound and the
reflected one must be at
least 0.1s
USES OF MULTIPLE REFLECTION
OF SOUND
Megaphones or loudhailers, horns,
musical instruments such as trumpets
and shehanais,
The audible range of sound for human beings
extends from about
20 Hz to 20000 Hz (one
Hz = one cycle/s
Children under the age of
five and some animals, such as dogs can hear
up to
25 kHz (1 kHz = 1000 Hz)
