Why electric dipole moment between two charges points from negative to positive charge.
The electric dipole moment between two charges points from the negative charge to the positive charge because it is defined as a vector quantity that points from the negative charge to the positive charge. In other words, the direction of the dipole moment is determined by convention.
To understand why the convention is set this way, we need to consider the concept of a dipole. A dipole is a system consisting of two charges of equal magnitude but opposite sign that are separated by a small distance. It is often represented by an arrow pointing from the negative charge to the positive charge.
One way to determine the direction of the dipole moment is to consider the torque experienced by the dipole in an external electric field. When a dipole is placed in an electric field, it experiences a torque that tends to align it with the field. This torque is maximum when the dipole moment is aligned opposite to the field direction. By convention, the direction of the dipole moment is defined to be from the negative charge to the positive charge, which means that it is opposite to the electric field when the dipole is aligned with the field.
It's important to note that the choice of convention is arbitrary, as long as it is consistent. In some situations, reversing the convention may be more convenient or appropriate. However, the convention of pointing the dipole moment from the negative to the positive charge is widely used and accepted in physics.