A conducting disc of radius r rotaes with a small but constant angular velocity `omega` about its axis. A uniform magnetic field B exists parallel to the axis of rotation. Find the motional emf between the centre and the periphery of the disc.

Explanation

To find the motional electromotive force (emf) between the center and the periphery of a conducting disc rotating in a uniform magnetic field, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Setup**:
- We have a conducting disc of radius \( r \) rotating about its axis with a constant angular velocity \( \omega \).
- A uniform magnetic field \( B \) is present parallel to the axis of rotation.

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