PHYSICS WK1- CH 1-4 THE BASICS AND SOUND WAVES

Vocabulary flashcards covering relationships, units, scientific notation, metric prefixes, and basic ultrasound wave concepts from Chapter 1.

Unrelated relationship

Two quantities with no apparent association; plotted as random dots with no recognizable pattern.

Related or proportional relationship

Two quantities are associated in some way, but the exact form of their relation is not specified.

Directly related

When one quantity increases, the other also increases (positive correlation).

Inversely related

When one quantity increases, the other decreases (inverse correlation).

Reciprocal relationship

Two numbers are reciprocals; their product equals one (e.g., 2 and 1/2).

Unit

A standard measurement accompanying a number to convey meaning (e.g., seconds, liters).

Pressure (acoustic variable)

Concentration of force in an area; measured in pascals.

Density (acoustic variable)

Concentration of mass in a volume; often expressed in kilograms per cubic centimeter (kg/cm^3) or kilograms per cubic meter (kg/m^3).

Distance (acoustic variable)

Measure of particle motion; typically in centimeters or millimeters in ultrasound.

Acoustic variables

Three properties used to describe sound waves: pressure, density, and distance.

Acoustic propagation properties

Effects of the medium on the sound wave (how the medium alters the wave).

Biologic effects

Effects of the sound wave on biological tissue as it passes through.

Sound wave / Acoustic wave

A mechanical wave where particles in a medium vibrate; cannot travel through a vacuum; travels through air, tissues, etc.

Longitudinal wave

Particles oscillate parallel to the direction of wave propagation; characteristic of sound waves.

Transverse wave

Particles oscillate perpendicular to the direction of wave propagation (e.g., a vibrating string).

Acoustic wave start and stop

Sound waves require a medium and travel in a straight line from source to receiver (conceptually).

Seven acoustic parameters

Period, frequency, amplitude, power, intensity, wavelength, and propagation speed describe a sound wave.

Period

Time for one complete cycle of a wave; reciprocal of frequency.

Frequency

Number of cycles per second; measured in hertz (Hz).

Amplitude

Maximum displacement of particles from their resting position (wave height).

Power

Rate at which energy is transferred by the wave; unit: watts (W).

Intensity

Power per unit area delivered by the wave; unit: watts per square meter (W/m^2).

Wavelength

Distance over which the wave repeats; related to speed and frequency by λ = c/f.

Propagation speed

Speed at which a sound wave travels in a given medium; unit: meters per second (m/s).

Sound cannot travel in a vacuum

Sound requires a medium (air, tissue, fluid) to propagate; no medium means no sound.

Example ultrasound frequency prefixes

Megahertz (MHz) denotes frequency; 3 MHz = 3,000,000 Hz. Prefixes like kilo-, mega-, micro-, nano- describe magnitudes.

Megahertz (MHz)

1,000,000 hertz; common unit for ultrasound transducer frequency.

Giga (prefix)

10^9 (billion).

Mega (prefix)

10^6 (million).

Kilo (prefix)

10^3 (thousand).

Milli (prefix)

10^-3 (one thousandth).

Micro (prefix)

10^-6 (one millionth).

Nano (prefix)

10^-9 (one billionth).

King Henry mnemonic

Phrase to remember metric-prefix order (e.g., King Henry Died By Drinking Chocolate Milk); helps convert between prefixes and base units.