Shielding gamma radiation effectively

Steps:

• Identify radiation types: alpha particles (helium nuclei), beta particles (electrons/positrons), gamma rays (high-energy photons).
• Note alpha and beta are low-penetrating, stopped by light materials like paper or plastic.
• Recognize gamma rays are highly penetrating, requiring dense materials for absorption.
• Select material: lead, due to high density and atomic number, blocks gamma rays via photoelectric effect and Compton scattering.

Why C is correct:

• Lead shields gamma rays effectively, as its high density (11.34 g/cm³) and atomic number (82) increase interaction probability with photons, per radiation attenuation laws.

Why the others are wrong:

• A. Copper: Moderate density (8.96 g/cm³) insufficient for gamma absorption; better for beta.
• B. Glass: Low density and brittle; allows gamma penetration, suitable only for alpha/beta.
• D. Plastic: Lightweight, stops alpha/beta via ionization but transmits gamma rays.

Final answer: C