Which of the following factors increases the ability to penetrate materials?

The ability to penetrate materials is significantly influenced by the energy of the radiation source. Higher energy sources possess greater penetrating power because they can interact with atomic structures more effectively than lower energy sources. This means that radiation from a higher energy source is able to overcome the binding forces in materials, allowing it to pass through more obstacles without being absorbed or scattered.

For instance, gamma rays and X-rays, which are forms of high-energy electromagnetic radiation, can penetrate human tissue and various materials more readily than lower energy forms of radiation, such as alpha particles. This property is crucial in applications like medical imaging and radiation therapy, where the objective often involves targeting tissue or materials at specific depths.

In contrast, factors such as longer wavelength and lower mass would generally correlate with lower penetration capability, and normal atmospheric pressure has a negligible effect on the inherent penetrating ability of radiation. Thus, the link between higher energy sources and enhanced penetration capability is a fundamental concept in radiation safety and physics.