Question

The breaking stress of a wire depends on:

• A. length of the wire
• B. radius of the wire
• C. material of the wire
• D. shape of the cross-section of the wire

Hint:

Distinguish between extrinsic and intrinsic properties. Extrinsic properties like mass, length, or breaking force depend on the amount or size of the object. Intrinsic properties like density, resistivity, or breaking stress depend only on the substance itself.

Answer 1

The Correct Option is C

Step 1: Concept Overview:
Breaking stress, also known as ultimate tensile strength (UTS), is a material's maximum stress capacity before failure under tension.
Step 2: Detailed Explanation:
Stress is force per unit area (\(\sigma = F/A\)). Breaking stress is an intensive property, determined by the material's internal structure and bonding, not its size.


Wire Length and Radius: These are geometric properties. While breaking {force} depends on the radius (since \(F = \sigma \times A\)), breaking {stress} (force per area) is independent of dimensions. Wires of the same material, regardless of thickness, break at the same stress.
Cross-Section Shape: Like length and radius, this geometric factor doesn't affect the material's intrinsic strength.
Wire Material: The material (e.g., steel, copper, aluminum) dictates atomic bond strength and microstructure, influencing the maximum stress the material can withstand. Therefore, breaking stress characterizes the material.

Step 3: Conclusion:
A wire's breaking stress is an intrinsic property dependent only on the wire's material.