Which material can stop a beta particle?

• A. Wood
• B. Glass
• C. Water
• D. Plastic

Answer: (A)

Beta particles are electrons with limited penetrating power, so the shielding only needs to be thick enough to absorb their energy. Materials with low density and low atomic numbers slow and stop these particles more effectively for a given thickness, and they also keep secondary radiation low.

Wood is a practical example of this shielding principle. Its relatively light, porous structure provides enough stopping distance for typical beta energies encountered in many lab or field scenarios, making a modest piece of wood an effective barrier. It’s inexpensive, readily available, and doesn't produce much secondary radiation, which helps keep shielding simple and safe.

Glass, water, and plastic can also stop beta particles if they’re thick enough, but the thickness required depends on the beta energy. In many common educational or small-scale contexts, wood is the easiest, most reliable choice, which is why it’s commonly cited as a material that can stop a beta particle.