Question

An electric dipole has the magnitude of its charge as q and its dipole moment is p. It is placed in a uniform electric field E. If its dipole moment is along the direction of the field, the force on it and its potential energy are respectively

• A. $2q \cdot E$ and minimum
• B. $q \cdot E$ and $p \cdot E$
• C. Zero and minimum
• D. $q \cdot E$ and maximum

Answer 1

Answer: (C)

Zero and minimum

Answer 2

In the given condition angle between $\overrightarrow{p}$ and $\overrightarrow{E}$ is zero. Hence potential energy $U = - pE\cos 0 = - pE = min.$

Also in uniform electric field F­_net = 0.