Question

An electric dipole experiences a torque 5√2 Nm when placed at the 45° in an uniform electric field .The magnitude of the potential energy of the dipole is
(a)2√2 J
(b)4√2 J
(c)5√2 J
(d)3√2 J

Answer 1

Answer:

ANSWER

Torque, τ=PEsin θ=2Qlsin θ

Here l is the length of the dipole, Q is the charge and E is the electric field.

Potential energy, U=−PEcos θ=−2Qlcos θ

Uτ=−2Qlcosθ2Qlsinθ     (where P=qd)   =−tanθUτ=−tanθU=−tan 600τ=−383=−8 joule