Which material is hard, strong, stiff, and an insulator, and is used for plug sockets and door handles?

• A. Polyester Resin
• B. Urea Formaldehyde
• C. Epoxy Resin
• D. Glass

Answer: (B)

Hard, strong, stiff materials that also insulate electricity are exactly the type of rigid thermosetting plastics suited for electrical hardware. Urea-formaldehyde resin cures into a hard, rigid polymer with high stiffness and excellent dielectric properties, so it doesn’t conduct electricity. That combination—rigid mechanical strength and good insulation—makes it ideal for things like plug sockets and door handles, where a solid, non‑conductive body is needed. The other options don’t fit as well: polyester resin is more flexible and used in composites; epoxy resin is very strong and versatile but is typically used for adhesives and coatings rather than standard electrical housings; glass is brittle and heavy for such hardware.