91影视

The right-hand rule states-1 (RHR-1) that the direction of the magnetic force on a moving charge is perpendicular to the plane formed by v and B.

Torque is defined as${}^{\mathfrak{r}=\mathrm{r}\mathbf{Fsin}\mathrm{胃}}$; where r is the distance, F is the applied force, and${}^{\mathrm{胃}}$is the angle between r and F.

1. According to RHR-1, the thumb is in direction of the velocity, and the fingers point in the direction of B.

2. That means for the top segment, the direction of velocity is from left to right, and force points in the direction perpendicular to the palm and upwards.

3. For the bottom segment, the direction of velocity is from right to left and force is perpendicular to the palm but pointing downwards.

4. Finally, the forces acting on the top and bottom segments are of equal magnitude but the direction is opposite, with one pointing vertically up and the other vertically down.

5. Therefore, these two forces produce no torque about the axis of rotation.

Let us draw the required segments,