InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
An electric dipole has two point charges of 1.6 × 10-19 C and -1.6 × 10-19 C separated by 2 A. If the dipole is placed in a uniform electric field of 10 N/C, making an angle of 300 with the dipole moment, find (i) the magnitude of the torque acting on the dipole due to the field (ii) the potential energy of the dipole. |
|
Answer» Data: q = 1.6 × 10-19 C, 2l = 2Å = 2 × 10-10 m, E = 10 N/C, θ = 30° Electric dipole moment, p = 2ql = q (2l) = (1.6 × 10-19 C)(2 × 10-10 m) = 3.2 × 10-29A∙m2 (j) The magnitude of the torque, τ = pE sin θ = (3.2 × 10-29 Am2 )(10 N/C) sin 30° = 3.2 × 10-28 × 0.5 = 1.6 × 10-28 N∙m (ii) The potential energy, U = -pE cosθ = -(3.2 × 10-29 A∙m2 )(10 N/C) cos30° = -3.2 × 10-28 × 0.866 = -2.771 × 10-28 J |
|