Calculate the magnetic field at point O for the current-carrying wire segment shown in Fig. The wire consists of two straight portions and a circular arc of radius a, which subtends an angle `theta`.

Explanation

To calculate the magnetic field at point O for the current-carrying wire segment consisting of two straight portions and a circular arc, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Components of the Wire**:
The wire consists of two straight segments (AA' and CC') and a circular arc (AC) of radius \( a \) that subtends an angle \( \theta \).

2. **Determine the Contribution from Straight Segments**:
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