Electric Dipole

An electric dipole is a pair of two objects having equal and opposite charges, separated by a distance.

What is Electric Dipole?

Suppose there are two charges of equal magnitude ‘q’, separated by a distance‘d’. Let the first charge be negative and the second charge be positive. This combination can be called as an electric dipole. Therefore, we can say that an electric dipole is created by the combination of equal and opposite charges by a separation of a certain distance.

Electric Dipole

Now, the electric dipole moment for this pair of equal and opposite charges is equal to the magnitude of the charges multiplied by the distance between them.

Magnitude of Electric Dipole Moment

\( \overrightarrow{p} \) = \( q \overrightarrow {d} \)

Direction of Electric Dipole Moment

Electric dipole moment is a vector quantity; it has a defined direction which is from the negative charge to the positive charge. Though, it is important to remember that this convention of direction is only followed in Physics. In Chemistry, the convention is taken to be opposite i.e. from positive to negative. The line along the direction of electric dipole is called the axis of the dipole.

Electric potential due to a Dipole (V)

Suppose there are two charges –q, placed at A, and +q placed a B, separated by a distance d, forming a dipole. Suppose the midpoint of AB is O.

The Electric potential due to a dipole at any point P, such that OP = r will be:

V = \(\frac{1}{4\pi \epsilon } \frac{p\cos \Theta }{r^{2}}\)

Case 1: If θ = 90°

Electric potential = V = 0

Case 2: If θ = 0°

Electric potential = V = \(\frac{1}{4\pi \epsilon } \frac{p }{r^{2}}\)

This was just an introduction to electric dipole.  To learn more on physics calculators download Byju’s.

Practise This Question

A rectangular coil 6 cm long and 2 cm wide is placed in a magnetic field of 0.02 T. If the loop contains 200 turns and carries a current of 50 mA, the torque on the coil when its area vector is perpendicular to the field will be?