An electric dipole of length 20 cm having ± 3 ×10-3 C charge placed at 60° with respect to a uniform electric field experiences a torque of magnitude 6 N m. The potential energy of the dipole is

Question

An electric dipole of length 20 cm having ± 3 ×10-3 C charge placed at 60° with respect to a uniform electric field experiences a torque of magnitude 6 N m. The potential energy of the dipole is (A) -2 √3 J (B) 5√3 J (C) -3 √2 J (D) 3 √5 J

Tardigrade Admin · Accepted Answer

Here, length of dipole, 2a = 20 cm = 20 × 10-2 m Charge q =± 3×10-3 C, θ=60° and torque τ=6 N m As τ=PEsin θ or E=(τ/P sin θ)=(τ/q(2a)sin θ) (∵ p=q(2a)) ∴ E=(6/3×10-3×20×10-2× sin 60°)=(105/5√3)N C-1 Potential energy of dipole, U =-pEcosθ=-q(2a)Ecosθ =-3×10-3(20×10-2)(105/5√3)cos 60° =(-3×10-5×20×105/5√3×2) =-2√3 J

Q. An electric dipole of length $20 c m$ having $\pm 3 \times 1 0^{- 3} C$ charge placed at $6 0^{\circ}$ with respect to a uniform electric field experiences a torque of magnitude $6 N m$ . The potential energy of the dipole is

$- 23 J$

$53 J$

$- 32 J$

$35 J$

Q. An electric dipole of length 20cm having ±3×10−3C charge placed at 60∘ with respect to a uniform electric field experiences a torque of magnitude 6Nm. The potential energy of the dipole is

−23​J

53​J

−32​J

35​J

Q. An electric dipole of length $20 c m$ having $\pm 3 \times 1 0^{- 3} C$ charge placed at $6 0^{\circ}$ with respect to a uniform electric field experiences a torque of magnitude $6 N m$ . The potential energy of the dipole is

$- 23 J$

$53 J$

$- 32 J$

$35 J$