Question

Which of the following is not a category of engineering materials?

• A. Metals
• B. Ceramics
• C. Polymers
• D. Liquids

Hint:

Remember the three major classes of solid engineering materials: metals, ceramics, and polymers. If an option doesn’t fit as a solid with structural utility, it's probably not an engineering material class.

Answer 1

The Correct Option is D

Engineering materials are substances used in the manufacturing of machines, structures, devices, and products. They are primarily classified based on their physical and chemical properties as well as their applications.
Main Categories of Engineering Materials:

• Metals: Strong, ductile, good conductors of heat and electricity. Examples: Iron, Aluminium, Copper.
• Ceramics: Brittle, heat-resistant, and insulating materials. Examples: Glass, porcelain, bricks.
• Polymers: Lightweight, corrosion-resistant materials made of long-chain molecules. Examples: Plastics, rubber, nylon.

Why not Liquids?

• Liquids are generally not considered a category of engineering materials because they do not possess fixed shapes or mechanical strength needed for structural or load-bearing applications.
• While fluids (including liquids) are used in various engineering systems (like lubricants or coolants), they are not classified alongside solids like metals, ceramics, and polymers, which form the core structural material classes.

Hence, the correct answer is Liquids.