In electrical insulation, the “dielectric strength” of a material refers to which characteristic?

Introduction / Context:
Dielectric strength is a key parameter for insulators in cables, capacitors, and high-voltage equipment. It informs how much electric field an insulator can tolerate before breakdown occurs and arcing starts.

Given Data / Assumptions:

• Voltage is applied across a uniform specimen of the insulating material.
• Breakdown is defined as the onset of sustained conduction through the insulator.

Concept / Approach:
Dielectric strength is the maximum electric field (often expressed as kV/mm) a material can withstand without failure. It is not merely resistance (ohmic property) or magnetic behavior; it specifically addresses breakdown under high electric fields.

Step-by-Step Solution:
1) Distinguish between resistivity and dielectric strength: resistivity describes conduction at low fields; dielectric strength concerns catastrophic failure at high fields.2) Breakdown occurs when charge carriers accelerate enough to cause ionization or when defects allow conduction paths.3) Therefore, dielectric strength quantifies withstanding high voltage without breakdown.

Verification / Alternative check:
Standards such as ASTM D149 define dielectric breakdown testing procedures confirming the high-voltage focus of this property.

Why Other Options Are Wrong:
Energy storage capacity: related to permittivity and capacitor design, not breakdown threshold.
Magnetic property: unrelated to dielectric behavior.
Resisting current flow: describes resistivity/insulation resistance, not breakdown field.
Thermal shock resistance: a mechanical/thermal property.

Common Pitfalls:
Confusing dielectric constant (permittivity) with dielectric strength; they measure different aspects of insulating performance.

Final Answer:
its capacity to withstand high voltage without electrical breakdown