CAOHC - Council for Accreditation in Occupational Hearing Conservation Physics of Sound and Anatomy 1

Question 1

The decibel (dB) scale used to measure sound intensity is best described as:

Accepted Answer

A logarithmic scale based on ratios relative to a reference pressure

Answer

The decibel scale is logarithmic, meaning each 10 dB increase represents a tenfold increase in intensity. It expresses sound levels as ratios relative to a reference pressure (20 µPa for airborne sound), which mirrors how the human ear perceives loudness differences.

Question 2

What is the primary role of the tympanic membrane (eardrum) in the hearing process?

Accepted Answer

It converts airborne sound pressure waves into mechanical vibrations

Answer

The tympanic membrane vibrates in response to incoming sound pressure waves, converting acoustic energy into mechanical motion that is then transmitted to the ossicular chain. This transduction step bridges the outer and middle ear.

Question 3

The Eustachian tube connects the middle ear to the:

Accepted Answer

Nasopharynx

Answer

The Eustachian tube links the middle ear cavity to the nasopharynx, allowing pressure equalization between the middle ear and ambient atmospheric pressure. Dysfunction can impair ossicular movement and reduce hearing sensitivity.

Question 4

If the frequency of a sound wave doubles, what happens to its wavelength (assuming the speed of sound remains constant)?

Accepted Answer

The wavelength is halved

Answer

Wavelength, frequency, and the speed of sound are related by the formula: speed = frequency × wavelength. Since the speed of sound in air is constant (~344 m/s), doubling the frequency requires the wavelength to be halved to maintain the equation.

Question 5

Along the basilar membrane within the cochlea, where are high-frequency sounds preferentially detected?

Accepted Answer

At the base near the oval window

Answer

The basilar membrane is tonotopically organized. High frequencies cause maximum displacement near the base (stiff, narrow region near the oval window), while low frequencies cause maximum displacement near the apex (flexible, wider region). This spatial mapping is fundamental to frequency discrimination.

CAOHC - Council for Accreditation in Occupational Hearing Conservation Practice Test

CAOHC - Council for Accreditation in Occupational Hearing Conservation Practice Test

CAOHC - Council for Accreditation in Occupational Hearing Conservation Physics of Sound and Anatomy 1