ARDMS Ultrasound Physics & Instrumentation Practice Exam

Which unit is commonly used to express acoustic pressure?

1. Pascals

2. Watts

3. Dollars

4. Volts

The correct answer is: Pascals

Acoustic pressure is a measure of the force exerted by sound waves on a surface area, and it is commonly expressed in Pascals (Pa). This unit is defined as one Newton per square meter (N/m²) and is the standard SI unit for measuring pressure. In the context of ultrasound physics, understanding acoustic pressure is crucial because it relates to the intensity and characteristics of the sound waves produced during imaging. The other units listed do not apply to acoustic pressure. Watts (a measure of power) express the rate of energy transfer and are relevant when discussing the intensity of ultrasound waves, whereas dollars have no relevance in the context of physical measurements. Volts measure electric potential difference and are used in electrical contexts rather than acoustic pressure.