M3 Physics

Acoustics is the section of physics, which studies:

• the mechanical oscillations and waves and their propagation in various media;

• the mechanical properties of living tissues and organs, and the mechanical phenomena, taking place in the body as a whole and in the organs;

• the properties of fluids.

Physiological acoustics studies:

• the work of the organs for sound detection and production in humans and animals;

• the work of the organs for digestion in humans and animals;

• the work of the heart in humans and animals.

Sound is:

• a mechanical wave with frequency from 20 Hz to 20000 Hz, causing a specific racion

  of the human auditory organ;

• an electromagnetic wave with frequency from 20 Hz to 20000 Hz, causing a specific reaction of the human auditory organ;

• a mechanical wave with intensity from 20 /m2 to 20000 W/m2, causing a specific reaction of the human auditory organ.

The frequency is

• inversely proportional to the period

• is directly proportional to the period;

• does not depend on the period.

The measurement unit for frequency is:

• hertz;

• watt/square meter;

• hertz/square meter.

Ultrasound is:

• a mechanical wave with frequency above 20 000 Hz;

• a mechanical wave with frequency below 20 000 Hz;

• an electromagnetic wave with frequency above 20 000 Hz.

Infrasound is:

• mechanical wave with frequency below 20 Hz;,

• a mechanical wave with frequency above 20 000 Hz;

• an electromagnetic wave with frequency below 20 Hz

The main subjective characteristics of the human auditory perceptions are:

• pitch, timbre, loudness;

• pitch, timbre, tone;

• pitch, timbre, intensity.

Spectral dependence of the hearing threshold is:

• the dependence of the hearing threshold on sound frequency;

• the dependence of the hearing threshold on sound intensity;

• the dependence of the hearing threshold on sound timbre.

Pain threshold is:

• the sound intensity for a given frequency, which results in a sensation of pain;

• the sound intensity for a given pitch, which results in a sensation of pain;

• the sound intensity for a given timbre, which results in a sensation of pain.