A current of 4A is flowing through a circular coil of radius 20 cm containing 200 turns. Find the magnetic flux density at the centre of the coil.

Explanation

To find the magnetic flux density at the center of a circular coil, we can use the formula:

\[ B = \frac{n \mu_0 I}{2r} \]

where:
- \( B \) is the magnetic flux density,
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