Temperature effect on dielectric constant without permanent dipoles State whether the following is true or false: “If a dielectric material has no permanent dipoles, then its dielectric constant is independent of temperature (over ordinary ranges).”

Introduction / Context:
The total permittivity of a dielectric arises from different polarization mechanisms: electronic, ionic, and orientational. Only the orientational (permanent dipole) component shows strong 1/T dependence in simple models. Understanding this helps predict how εr varies with temperature.

Given Data / Assumptions:

• No permanent dipoles (nonpolar material).
• Linear, homogeneous, isotropic; small-signal fields.
• “Ordinary ranges” excludes phase transitions near Curie points.

Concept / Approach:
In nonpolar dielectrics, polarization is primarily electronic and sometimes ionic. These mechanisms depend weakly on temperature compared with orientational polarization found in polar materials. Therefore, εr is approximately temperature independent, aside from small variations due to lattice expansion or subtle phonon effects.

Step-by-Step Solution:
Identify absence of orientational polarization (no permanent dipoles).Recognize electronic/ionic polarization weak temperature dependence.Conclude εr is nearly constant with temperature in typical conditions → statement true.

Verification / Alternative check:
Handbook data for nonpolar polymers (e.g., polyethylene) and ceramics (e.g., quartz far from phase transitions) show small εr variations with T compared with polar dielectrics like water or alcohols.

Why Other Options Are Wrong:
“False” or “always increases strongly” contradicts the known weak dependence. “True only at very high temperatures” is unnecessary qualification. “Cannot be predicted” ignores established polarization theory.

Common Pitfalls:

• Confusing temperature-dependent dielectric loss (tan δ) with large changes in εr.
• Overlooking anomalies near structural phase transitions; those are outside the assumed range.

Final Answer:
True