For a parallel-plate capacitor, which set of physical factors primarily determines its capacitance value in practice, assuming ideal geometry?

Introduction:
Capacitance is a geometric and material property that dictates how much charge a capacitor stores per volt. This question asks you to identify the parameters that directly appear in the capacitance expression for an ideal parallel-plate structure.

Given Data / Assumptions:

• Parallel-plate approximation.
• Uniform dielectric fills the gap.
• Fringing and losses neglected.

Concept / Approach:
The ideal formula is C = (epsilon_r * epsilon_0 * A) / d, where A is plate area, d is separation, epsilon_r is dielectric constant, and epsilon_0 is vacuum permittivity. These factors directly control capacitance.

Step-by-Step Solution:
1) Start from C = (epsilon_r * epsilon_0 * A) / d.2) Identify variables: A increases C linearly; larger epsilon_r increases C; larger d reduces C.3) Recognize that dielectric strength and temperature coefficient affect ratings and stability, not the first-order ideal C value.

Verification / Alternative check:
Compare two capacitors with same A and d but different materials; the one with larger epsilon_r always has larger capacitance, confirming the direct dependence on dielectric constant.

Why Other Options Are Wrong:
Temperature coefficient: influences change with temperature, not base value.Voltage rating: mostly tied to dielectric strength and construction safety, not C directly.Dielectric strength: a breakdown property; does not set C in the ideal formula.

Common Pitfalls:
Confusing dielectric strength (breakdown) with dielectric constant (permittivity). They are different properties with different roles.

Final Answer:
Plate area, dielectric constant, and plate separation