Permittivity concepts — interpreting ε0 versus εr in terms of material microstructure Which statement best reflects the physical interpretability of absolute permittivity ε0 and relative permittivity εr?

Introduction / Context:
Permittivity describes how electric fields interact with matter. The vacuum permittivity ε0 is a fundamental constant of nature, while the relative permittivity εr captures the additional polarization response due to a material’s microscopic structure.

Given Data / Assumptions:

• Linear, isotropic dielectrics.
• Microscopic interpretation via dipole polarizability.
• SI units and conventional definitions: ε = ε0 εr.

Concept / Approach:
ε0 characterizes empty space and is not derived from specific atomic properties. εr, however, depends on how bound charges within atoms and molecules displace under an applied field; models such as Clausius–Mossotti relate εr to microscopic polarizability. Thus εr, not ε0, is interpretable in terms of the material’s atomic-scale properties.

Step-by-Step Solution:
Write ε = ε0 εr.Associate εr with polarization P via P = ε0 (εr − 1) E.Relate P to dipole density and polarizability → microstructural interpretation applies to εr.

Verification / Alternative check:
The Clausius–Mossotti relation (εr − 1)/(εr + 2) = (N α)/(3 ε0) explicitly ties εr to number density N and polarizability α, confirming the statement.

Why Other Options Are Wrong:
(a) incorrectly attributes medium-dependent atomic interpretation to ε0. (c) reverses roles. (d) denies the well-established significance of εr. (e) dismisses both constants, which is incorrect.

Common Pitfalls:

• Confusing absolute and relative permittivity roles.
• Assuming ε0 varies with environment; it does not.

Final Answer:
Only εr can be interpreted in terms of the atomic properties of the medium