Which category includes a refractory inorganic nonmetallic material baked from clay at high temperatures?

• A. Ceramics
• B. Glass
• C. GRP
• D. Composite

Answer: (A)

This question tests how materials are categorized by how they’re made and what they’re made from. A material baked from clay at high temperatures becomes a ceramic. Ceramics are inorganic nonmetallic solids produced by shaping clay and firing it to high temperatures, which gives them hardness and high heat resistance (refractoriness). Glass is also inorganic and nonmetallic, but it’s made by melting silica and other ingredients and then cooling into a noncrystalline solid rather than firing clay. GRP and other composites involve polymers and reinforcements, so they aren’t inorganic nonmetallic materials formed by baking clay. So the category that fits is ceramics.