Why eddy currents are undesirable in the core of transformers?

Explanation

### Step-by-Step Solution:

1. **Understanding Eddy Currents**: Eddy currents are loops of electrical currents that are induced within a conductor when it is exposed to a changing magnetic field. This phenomenon occurs due to Faraday's law of electromagnetic induction.

2. **Eddy Currents in Transformers**: In transformers, an alternating magnetic field is applied to a magnetic core made of conducting material. This changing magnetic field induces an electromotive force (EMF) in the core material.

3. **Formation of Eddy Currents**: The induced EMF causes circulating currents within the core material. These circulating currents are referred to as eddy currents.

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