Difficulty: Easy
Correct Answer: False
Explanation:
Introduction / Context:Transformers enable voltage level changes and isolation using electromagnetic induction. This question distinguishes the roles of windings and core, and the difference between electrical versus magnetic coupling.
Given Data / Assumptions:
Concept / Approach:
A standard transformer has two or more windings (coils) magnetically coupled via a common magnetic core. The coupling mechanism is magnetic (via changing flux), not electrical. Saying “electrically coupled cores” confuses the terminology: it is windings that are placed on one core, and they are magnetically coupled.
Step-by-Step Solution:
Primary winding on a magnetic core is energized with AC, producing alternating flux.This flux links to other windings on the same core, inducing voltages proportional to turns.Coupling is magnetic: V_secondary / V_primary = N_secondary / N_primary (ideally).There is no requirement for “two or more cores,” and the coupling is not electrical between cores.Verification / Alternative check:
Open any basic transformer diagram: a single core with multiple windings. Equivalent circuits use magnetizing inductance and mutual inductance, emphasizing magnetic, not electrical, coupling.
Why Other Options Are Wrong:
All “True …” choices misstate the fundamental structure. Three-phase cores may use three legs but still rely on magnetic coupling of windings placed on the same laminated core, not “electrically coupled cores.”
Common Pitfalls:
Confusing the phrase “electromagnetic induction” with “electrical coupling,” and mixing up the role of the core (provides a flux path) versus windings (provide turns ratio and carry current).
Final Answer:
False
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