How is mutual inductance of a pair of coils affected when (i) separation between the coils in increased, (ii) the number of turns of each coil is increased , (iii) a thin iron sheet is placed between the two coils, other factors remaining the same ? Explain your answer in each case.

Explanation

To solve the question regarding how the mutual inductance of a pair of coils is affected under different conditions, we will analyze each case step by step.

### Step-by-Step Solution:

1. **Effect of Increasing Separation Between the Coils:**
- **Explanation:** When the separation between the two coils is increased, the magnetic flux linking the secondary coil due to the current flowing in the primary coil decreases. This is because the magnetic field strength diminishes with distance. As a result, the mutual inductance (M) decreases.
- **Conclusion:** **Mutual inductance decreases** with increased separation.

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