Dielectric behavior check: Is it correct to say that no dielectric material exhibits hysteresis (i.e., polarization does not depend on the previous electric-field history)?
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ATrue — dielectrics show no hysteresis
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BFalse — many dielectrics (especially ferroelectrics) exhibit dielectric hysteresis
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CTrue only at very high frequency
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DTrue only at cryogenic temperature
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ETrue for liquids but not solids
Answer
Correct Answer: False — many dielectrics (especially ferroelectrics) exhibit dielectric hysteresis
Explanation
Introduction / Context:Polarization in dielectric materials can follow the applied electric field along a path that depends on prior excitation. The presence or absence of hysteresis is crucial in capacitor dielectrics, non-volatile memories, sensors, and actuators.
Given Data / Assumptions:
- Dielectric classes considered: linear, nonlinear, and ferroelectric materials.
- Quasi-static field cycling to observe polarization–electric field (P–E) behavior.
- Room-temperature behavior unless otherwise noted.
Concept / Approach:Linear dielectrics follow P = ε0 χ E without hysteresis. However, ferroelectric materials (e.g., BaTiO3, PZT) show spontaneous polarization that can be reversed by an external field, producing a characteristic P–E loop (dielectric hysteresis). Relaxor and some polymer ferroelectrics also show history-dependent response. Thus the blanket statement that no dielectric has hysteresis is false.
Step-by-Step Solution:
Define hysteresis: output (polarization) depends on input history (electric field).Identify classes: linear dielectrics (no hysteresis) vs. ferroelectrics (with hysteresis).Conclude the statement is false due to ferroelectric examples.Verification / Alternative check:
Measure a P–E loop using a Sawyer–Tower circuit; ferroelectrics show remanent polarization and coercive field.Why Other Options Are Wrong:
Options asserting universal absence of hysteresis ignore a large class of materials.Frequency or temperature caveats do not make the universal statement true.Common Pitfalls:
Assuming behavior of ideal capacitors applies to all dielectrics; overlooking ferroelectric phase transitions.Final Answer:
False — many dielectrics (especially ferroelectrics) exhibit dielectric hysteresis