Question

Which mechanical property of a metal represents its ability to resist permanent deformation?

• A. Elasticity
• B. Plasticity
• C. Hardness
• D. Toughness

Hint:

Logic Tip: Think of diamonds! A diamond is incredibly hard because you cannot scratch or permanently dent it. However, it is not very tough, because if you hit it with a heavy hammer, it shatters instead of bending.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Mechanical properties define how a material responds to applied forces. Resistance to "permanent deformation" specifically refers to surface or localized deformation like scratching, indentation, or wear.
Step 2: Key Formula or Approach:
Distinguish between bulk deformation (elasticity/plasticity) and surface resistance (hardness).
Step 3: Detailed Explanation:

Elasticity: The ability to return to original shape after removing a load.
Plasticity: The ability to undergo permanent deformation without breaking.
Hardness: The resistance of a material to localized plastic deformation (e.g., a small dent or scratch). Therefore, it represents the ability to resist permanent deformation at the surface level.
Toughness: The ability to absorb energy and deform plastically before fracturing.

Step 4: Final Answer:
Hardness is the property that represents the ability to resist permanent deformation.