Define coefficient of mutual induction,

Explanation

### Step-by-Step Solution

1. **Understanding Mutual Induction**:
- Mutual induction refers to the phenomenon where a change in electric current in one coil induces an electromotive force (EMF) in a nearby coil. This occurs due to the changing magnetic field created by the current in the first coil.

2. **Defining Coefficient of Mutual Induction**:
- The coefficient of mutual induction (denoted as \( M \)) quantifies the relationship between the change in current in one coil and the resulting magnetic flux in another coil. It indicates how effectively a coil can induce EMF in another coil.

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