What type of radiation has limited penetrability compared to ionizing radiation?

Ultraviolet (UV) radiation is the correct type of radiation that has limited penetrability compared to ionizing radiation. UV radiation is part of the electromagnetic spectrum and is generally unable to penetrate materials deeply; it primarily affects the outer layers of skin and tissues. Ionizing radiation, on the other hand, such as X-rays, has significantly higher energy and can penetrate deeper into materials and biological tissues, causing ionization in atoms. This property is what makes ionizing radiation particularly concerning in terms of health effects, as it can damage DNA at a cellular level.

When considering the other options, X-rays are a form of ionizing radiation and have a much greater penetrating ability than UV radiation. Infrared radiation is mainly associated with heat and has a longer wavelength than UV, resulting in limited penetration as well; however, it does not ionize atoms. Similarly, radio waves have even longer wavelengths and are not capable of ionization, but they too have limited penetrability, albeit for different reasons. Therefore, UV radiation stands out in this context due to its specific qualities related to its energy levels and effects.