Which one of the following polymers is widely used for making bullet proof material ?

The correct answer is Option 4: Polycarbonates.

Polycarbonates are a group of thermoplastic polymers known for their exceptional impact resistance, high strength, and optical clarity. In the manufacturing of bullet-proof materials, specifically bullet-resistant glass (often called "bullet-proof glass"), polycarbonate layers are laminated between sheets of ordinary glass. While the glass layers provide hardness, the polycarbonate layers provide the necessary toughness and elasticity to absorb and dissipate the energy of a high-velocity projectile, preventing penetration.

• Polyvinyl chloride (PVC): Used for pipes and cables, but lacks the impact resistance required for ballistic protection.
• Polyamides: While Aramid fibers (a specific type of polyamide) like Kevlar are used in bullet-proof vests, "Polyamides" is a broad category usually associated with Nylon, which is not the primary material for rigid bullet-proof panels.
• Polyethylene: High-density variants are used in some armor, but Polycarbonates are the standard for transparent bullet-proof applications.

Therefore, due to its unique ability to withstand high impact without shattering, Polycarbonate is the most widely used polymer for rigid bullet-proof materials.