Which statement about high-frequency therapy is true?

• A. It reduces ozone generation.
• B. It does not affect the surface of the skin.
• C. It generates ozone which has a germicidal effect on the surface of the skin.
• D. It cools the skin.

Answer: (C)

High-frequency therapy works by delivering a high-frequency electrical current through a glass electrode filled with inert gas. The discharge ionizes oxygen in the surrounding air, forming ozone. Ozone is a potent oxidizer with germicidal properties, so it helps disinfect the surface of the skin as part of the treatment. This is why the statement about generating ozone with a germicidal effect on the skin’s surface is true.

The other options don’t fit because the process actually produces—not reduces—ozone; it does affect the surface by stimulating and warming the skin rather than leaving it untouched, and it tends to produce a warming sensation rather than cooling.