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 semi-circle, we can follow these steps:

### Step 1: Understand the Initial Dipole Moment
The initial dipole moment \( m \) of a straight magnetic needle can be expressed as:
\[ m = p \cdot l \]
where \( p \) is the pole strength and \( l \) is the total length of the needle.
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