Standing waves in therapeutic ultrasound create which effect?

Standing waves in therapeutic ultrasound create which effect?

• A. Increase in intensity and pressure
• B. Decrease in intensity
• C. No change
• D. Random fluctuations

Answer: (A)

Standing waves form when the ultrasound wave reflects back and interferes with the incoming wave. This creates a pattern of points of constructive interference (antidodes) and destructive interference (nodes). At the antinodes, the pressure and particle motion add together, producing a larger amplitude. Since intensity rises with the square of the pressure, these regions experience increased intensity and pressure compared with the surrounding traveling-wave energy. This is why standing waves in therapeutic ultrasound lead to localized hotspots of higher energy. The other options don’t fit because a standing wave isn’t a global decrease or no change in energy—it’s a spatial variation with alternating high and low energy. It’s not random fluctuations but a predictable pattern of alternating intensity.

Standing waves form when the ultrasound wave reflects back and interferes with the incoming wave. This creates a pattern of points of constructive interference (antidodes) and destructive interference (nodes). At the antinodes, the pressure and particle motion add together, producing a larger amplitude. Since intensity rises with the square of the pressure, these regions experience increased intensity and pressure compared with the surrounding traveling-wave energy. This is why standing waves in therapeutic ultrasound lead to localized hotspots of higher energy.

The other options don’t fit because a standing wave isn’t a global decrease or no change in energy—it’s a spatial variation with alternating high and low energy. It’s not random fluctuations but a predictable pattern of alternating intensity.