A thin magnetic needle is bent to form a semi-circle . What will be the percentage change in equivalent dipole moment ?

Explanation

To solve the problem of finding the percentage change in the equivalent dipole moment when a thin magnetic needle is bent to form a semicircle, we can follow these steps:

### Step 1: Understand the Magnetic Moment
The magnetic moment (M) of a magnetic needle is given by the formula:
\[ M = m \cdot L \]
where \( m \) is the pole strength and \( L \) is the effective length of the needle.

### Step 2: Determine the Effective Length of the Semicircle
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