If you double the frequency of an ultrasound wavewhat happens to depth penetration?

Depth penetration decreases.

The penetration depth of an ultrasound wave is inversely proportional to the square root of its frequency. This means that as the frequency of an ultrasound wave increases, its penetration depth decreases. Doubling the frequency of an ultrasound wave will reduce its penetration depth by a factor of the square root of 2, or approximately 1.41.