Question

An electric dipole consists of two equal and opposite charges, +q and −q, separated by a small distance 2a. What is the magnitude of its dipole moment and in which direction is it directed?

Options

• \[p = q \times a\], directed from \[+q\] to \[-q\]

• \[p = q \times 2a\], directed from \[-q\] to \[+q\]

• \[p = q \times 2a\], directed from \[+q\] to \[-q\]

• \[p = \frac{q}{2a}\], directed from \[-q\] to \[+q\]

Answer 1

The dipole moment has magnitude p = q × 2a (charge multiplied by separation) and, by convention, is directed from the negative charge −q to the positive charge +q. This direction defines the dipole axis used in all potential calculations.