There is _____ penetration with higher frequencies.

• A. Less
• B. More
• C. Same
• D. Variable

Answer: (A)

Higher frequency waves lose more energy as they travel through a medium, so their penetration depth is reduced. In ultrasound, the attenuation coefficient in soft tissue increases with frequency, so doubling the frequency increases energy loss per centimeter and cuts how deep the wave can go before it becomes too weak to detect. That’s why higher frequencies give better resolution but shallower penetration. So the statement is that there is less penetration with higher frequencies. The other options don’t fit because more penetration would require lower attenuation, the same penetration would ignore the frequency dependence, and variable penetration would suggest inconsistent behavior across tissues, which isn’t the general case.