Which type of radiation has the highest penetrating ability?

Gamma rays possess the highest penetrating ability among the types of radiation listed. This is due to their nature as high-energy electromagnetic waves, which allows them to pass through materials, including biological tissues, more effectively than both alpha and beta particles.

Alpha particles are relatively heavy and carry a positive charge, which limits their penetration ability significantly. They can be stopped by just a few centimeters of air or a sheet of paper. Beta particles, being lighter and possessing a negative charge, can penetrate further than alpha particles but are still unable to traverse dense materials like lead or thick concrete.

In contrast, gamma rays and X-rays are both forms of electromagnetic radiation, but gamma rays have higher energy than X-rays. This higher energy allows gamma rays to penetrate dense materials much more effectively, making them capable of passing through several centimeters of lead. This property is essential in radiation therapy and radiographic imaging because it allows these forms of radiation to target and image internal structures in a way that lower-energy radiation cannot.