A dipole has moment

PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Electric Force Field and Potential · Electric Force Field and Potential

Problem

A dipole has moment

3.2\times10^{-29}\,\text{C}\,\text{m}

. When placed in a certain uniform electric field it possesses a potential energy of

+1.6\times10^{-21}\,\text{J}

at an orientation angle of

120^{\circ}

relative to the field. (i) Calculate the magnitude of the electric field. (ii) The dipole is now rotated so that its potential energy becomes

-1.6\times10^{-21}\,\text{J}

. Find the new angle between the dipole axis and the field.