What type of radiation is emitted by Uranium-235?

Uranium-235 primarily emits alpha particles during its radioactive decay process. Alpha particles consist of two protons and two neutrons, making them relatively heavy and positively charged. As Uranium-235 undergoes alpha decay, it releases these particles along with energy, leading to the formation of a different element, Thorium-231, in the process.

Understanding alpha radiation is key in radiological fundamentals; it has limited penetration power and can be effectively stopped by a sheet of paper or even the outer layer of human skin. However, if alpha-emitting materials are ingested or inhaled, they can cause significant biological harm due to their mass and charge, which allows them to interact strongly with matter.

While uranium can emit gamma rays, particularly when it is undergoing fission or when decay products emit gamma radiation, the primary decay mode for Uranium-235 involves alpha particle emission. Thus, alpha particles are the most significant type of radiation emitted directly by Uranium-235, making this the correct answer.