Which type of x-rays has greater penetrating power?

The correct choice identifies that short wavelength x-rays possess greater penetrating power. This is due to the fundamental relationship between wavelength and energy in the electromagnetic spectrum. Shorter wavelengths correspond to higher energy photons, which can penetrate matter more effectively than longer wavelengths.

In practical terms, short wavelength x-rays are utilized in various medical imaging applications because they can pass through soft tissues while being absorbed by denser materials, such as bone. This characteristic allows for clearer imaging and helps in diagnosing various conditions.

By contrast, longer wavelengths carry less energy and are less capable of penetrating materials, which is why they are not used for diagnostic imaging in contexts where higher penetration is necessary. This principle is central to understanding how different types of radiation interact with matter and is a key consideration in radiographic practices.