Describing Sound Waves

These flashcards cover the key concepts and parameters related to sound waves from the lecture notes, helping to reinforce understanding for the exam.

What are the seven parameters that describe a sound wave?

1. Period 2. Frequency 3. Amplitude 4. Power 5. Intensity 6. Wavelength 7. Propagation speed.

What is the definition of Period in relation to sound waves?

The time it takes a wave to vibrate a single cycle, from start of one cycle to start of the next cycle.

What units are used to measure Period?

Microseconds (µ).

What is the frequency range for Infrasound, Audible sound, and Ultrasound?

Infrasound: less than 20Hz; Audible sound: between 20Hz to 20kHz; Ultrasound: greater than 20kHz.

What is the relationship between frequency and period?

They are inversely related, demonstrating a reciprocal relationship.

What is the formula that shows the relationship between frequency and period?

Period x Frequency = 1.

What are the three bigness parameters of sound waves?

Amplitude, Power, Intensity.

How is Amplitude defined in the context of sound waves?

The 'bigness' of a wave, defined as the difference between the maximum value and the average value of an acoustic variable.

What are the typical units used to measure Amplitude?

Decibels (dB).

What is the definition of Power in relation to sound waves?

The rate of energy transfer or the rate at which work is performed, describing the 'bigness' of a wave.

What units are used to measure Power?

Watts.

How is Intensity defined in the context of sound waves?

The concentration of energy in a sound beam.

What are the typical units for measuring Intensity?

Watts per square centimeter (W/cm²).

What relationships exist among Power, Amplitude, and Intensity?

They are directly related; all describe the magnitude or strength of a wave.

What is the formula showing how Power relates to Amplitude?

Power ∝ Amplitude².

What is the definition of Wavelength in sound waves?

The distance or length of one complete cycle.

What units are used to measure Wavelength?

Millimeters (mm) or meters.

How does wavelength relate to frequency?

Wavelength is inversely related to frequency; as frequency increases, wavelength decreases.

What is the formula that demonstrates the relationship between wavelength and frequency?

λ = c/f (where c is the speed of sound and f is the frequency).

What is Propagation speed in relation to sound waves?

The rate at which a sound wave travels through a medium.

What are the typical units used to measure Propagation speed?

Meters per second or mm/µs.

What characteristics of the medium determine the speed of sound?

Stiffness (bulk modulus) and Density.

Which characteristic has the greatest influence on the speed of sound?

Stiffness.

What happens to the speed of sound when stiffness increases?

Speed increases.

What are two terms that mean the opposite of stiffness?

Elasticity and compressibility.