Intensities are reported with units of?

Intensities are reported with units of?

• A. W/m2
• B. Pa
• C. W/cm2
• D. dB

Answer: (C)

Intensities are a measure of how much power is crossing a surface per unit area. In imaging contexts like ultrasound, the surface of interest is typically small (on the scale of square centimeters), so intensity is commonly expressed as watts per square centimeter (W/cm^2). This convention reflects both the small-area nature of the region being analyzed and the practical need to quantify energy delivery to tissue. Pa is a unit of pressure, not power per area, and dB is a logarithmic level ratio, not an absolute intensity. While W/m^2 is the SI unit for radiant flux density, the standard, widely used unit in this particular context is W/cm^2, which is why that option is correct.

Intensities are a measure of how much power is crossing a surface per unit area. In imaging contexts like ultrasound, the surface of interest is typically small (on the scale of square centimeters), so intensity is commonly expressed as watts per square centimeter (W/cm^2). This convention reflects both the small-area nature of the region being analyzed and the practical need to quantify energy delivery to tissue.

Pa is a unit of pressure, not power per area, and dB is a logarithmic level ratio, not an absolute intensity. While W/m^2 is the SI unit for radiant flux density, the standard, widely used unit in this particular context is W/cm^2, which is why that option is correct.