The speaker is discussing the concept of torque in a dipole placed in a uniform electric field. The dipole consists of equal and opposite charges separated by a small distance. The electric field is uniform and the dipole experiences a force due to the electric field. This force is given by the formula F = Q*E, where Q is the charge and E is the electric field.
The force experienced by the dipole is along the direction of the electric field and is equal in magnitude but opposite in direction for the two charges. These forces form a couple, causing the dipole to experience a torque. The torque is given by the formula T = P*sin(Theta), where P is the dipole moment and Theta is the angle between the dipole moment and the electric field.
The speaker then discusses the case where the dipole is along the direction of the electric field (Theta = 0°). In this case, the torque is maximum. If the dipole is perpendicular to the electric field (Theta = 90°), the torque is minimum. If the dipole is at an angle of 180° (Theta = 180°), the torque is zero, but this position is unstable.
The speaker concludes the discussion by stating that the torque is zero when the dipole is at an angle of 180°, but this position is unstable.
1. The speaker is discussing the concept of torque on a dipole placed in a uniform electric field.
2. The dipole consists of equal and opposite charges separated by a small distance.
3. The dipole experiences a force in the direction of the electric field.
4. The force experienced by the charge is given by the formula F = Q * E, where Q is the charge and E is the electric field.
5. The force experienced by the opposite charge is also given by the same formula, but the direction is opposite to the electric field.
6. The two forces are equal but opposite in direction, forming a couple.
7. The dipole experiences a torque, which is usually given by the formula T = p * sin(Theta), where p is the dipole moment and Theta is the angle between the dipole and the electric field.
8. The perpendicular distance between the forces can be found using the sine of the angle Theta.
9. The dipole is rotating with respect to the electric field.
10. The torque is maximum when the dipole is perpendicular to the electric field (Theta = 90°), and minimum when the dipole is parallel to the electric field (Theta = 0°).
11. The torque is zero when the dipole is aligned with the electric field (Theta = 180°), which is an unstable state.