An electric dipole, of length 2 cm , is placed with its axis making an angle 30° with a uniform electric field. If it experiences a torque of 10√3 N m , then potential energy of the dipole is

Question

An electric dipole, of length 2 cm , is placed with its axis making an angle 30° with a uniform electric field. If it experiences a torque of 10√3 N m , then potential energy of the dipole is (A) -10 J (B) -20 J (C) -30 J (D) - 40 J

Tardigrade Admin · Accepted Answer

τ = PE sin 30 10√3 = (P E/2) PE = 20√3 Potential energy = -PE cos 30 potential energy = -20√3 × (√3/2) = - 10 × 3 = -30 J

Q. An electric dipole, of length $2 c m$ , is placed with its axis making an angle $3 0^{\circ}$ with a uniform electric field. If it experiences a torque of $103 N m$ , then potential energy of the dipole is

$- 10 J$

$- 20 J$

$- 30 J$

$- 40 J$

$τ = PE s in 30$
$103 = \frac{PE}{2}$
$PE = 203$
Potential energy = $- PE cos 30$
potential energy = $- 203 \times \frac{3}{2}$
$= - 10 \times 3 = - 30 J$

Q. An electric dipole, of length 2cm , is placed with its axis making an angle 30∘ with a uniform electric field. If it experiences a torque of 103​Nm , then potential energy of the dipole is

−10J

−20J

−30J

−40J