Define self-inductance of a coil . Write its S.I. units ?

Explanation

### Step-by-Step Solution:

1. **Definition of Self-Inductance**:
- Self-inductance of a coil is defined as the phenomenon where an induced electromotive force (EMF) is generated in the coil due to a change in the current flowing through the same coil. This occurs because a changing current produces a changing magnetic flux, which induces an EMF according to Faraday's law of electromagnetic induction.

2. **Mathematical Representation**:
- The magnetic flux (Φ) linked with the coil is directly proportional to the current (I) flowing through it. This relationship can be expressed as:
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