Elastic recovery of wire length after load removal

Steps:

• Suspended masses apply tension, causing elastic extension of the wire.
• Removing masses eliminates the tension.
• The wire recoils to its original unstretched length per elastic properties.
• Intrinsic material properties remain unaffected by this reversible deformation.

Why B is correct:

• Hooke's law states that extension is proportional to applied force (F = kx); removing force reverses extension, restoring original length.

Why the others are wrong:

• A: Half-life is a constant nuclear decay property, independent of mechanical stress.
• C: Wire's mass is fixed; removed masses are external and do not alter the wire itself.
• D: Melting point is an intrinsic thermal property of the metal, unchanged by elastic deformation.

Final answer: B