Which of the following materials is best suited for shielding against beta radiation?

Plastic is indeed an optimal choice for shielding against beta radiation due to its low atomic number and relatively high hydrogen content. Beta particles, which are high-energy, high-speed electrons or positrons, can penetrate materials to varying degrees. While denser materials like lead are effective at stopping gamma rays, they are not as effective against beta particles because beta radiation can actually produce secondary radiation when interacting with high-Z materials.

Plastic, on the other hand, effectively absorbs beta particles by providing a medium that allows the electrons to lose energy through ionization and excitation of the molecules within the plastic. This absorption occurs efficiently because the material’s composition can slow down the beta particles sufficiently to completely stop them as they undergo energy loss mechanisms. Thus, using materials like plastic for beta radiation shielding minimizes not only the risk of secondary radiation but also provides a lightweight and flexible option for protection.