When is the couple acting on a bar magnet in a uniform magnetic field (i) maximum (ii) minimum.

Explanation

To determine when the couple acting on a bar magnet in a uniform magnetic field is maximum and minimum, we can follow these steps:

### Step-by-Step Solution

1. **Understanding the Concept of Torque (Couple)**:
The torque (or couple) acting on a bar magnet in a magnetic field is given by the formula:
\[
\tau = \mathbf{m} \times \mathbf{B}
...