Phy Flashcards
……… Refers to frequencies below 20Hz
Infrasonic
Sound is a…… Wave
Longitudinal
……….refers to frequencies above 20kHz
Ultrasonic
The…….. Of a sound wave is the energy carried through unit area per second
Intensity
The ratio of two sound intensities is usually expressed in…….
Decibels
What is the amplitude of displacement of air molecules at the limit of hearing in humans?
One atom
The……… Of a tone is a perceived quantity
Loudness
Loudness depends on………. And………. Of sound waves
Intensity and frequency
What is the unit of loudness?
Phon
The………….. Of a medium is defined as Z=pv
Acoustic impedance
Materials with similar acoustic impedances is called…….
Impedance matching
…………. Occurs at positions where the waves arrive in phase
Constructive interference
Antinodes are and example of
Destructive interference
What parts make up the outer ear?
The pinna, auditory canal, eardrum
What is the resonant frequency of the ear canal?
3400Hz
What does the middle ear consist of?
Hammer, anvil and stirrup
What does the inner ear consist of?
Fluid filled, spiral shaped cochlea.
What does the outer ear do?
Gathers sound waves
What does the middle ear do?
Amplifies sound
What does the inner ear do?
Hair cells convert the sound vibrations into coded nerve pulses which are transmitted to the auditory cortex of the brain.
Define the solid state
Molecules oscillate about more or less fixed centres.
Long range order
Define the liquid state
Intermolecular distances and amplitudes are slightly larger than solids. Centres are free to move.
Short range order
Define the gas state
Molecules have much greater kinetic energy. Small attractive forces. The
Is elasticity reversible?
Yes
In stress and strain, force transmitted throughout the object if…….
Stationary
Define stress
Force divided by area
