An electric dipole with dipole moment ' p ' is placed with its axis at 30° to a uniform electric field. The work done in rotating the dipole to a position where its axis is perpendicular to the field is

Question

An electric dipole with dipole moment ' p ' is placed with its axis at 30° to a uniform electric field. The work done in rotating the dipole to a position where its axis is perpendicular to the field is (A) 2 p E (B) (2 p E/√3) (C) (√3 p E/2) (D) 0

Tardigrade Admin · Accepted Answer

Given, for an electric dipole, θ1=30° θ2=90° ∴ Work done in rotating the dipole from θ1=30° to a position, where its axis is perpendicular (θ2=90°) to electric field is given as W=p E( cos θ1- cos θ2) =p E( cos 30°- cos 90) =p E((√3/2)-0)=((√3/2) p E°)

Q. An electric dipole with dipole moment ' $p$ ' is placed with its axis at $3 0^{\circ}$ to a uniform electric field. The work done in rotating the dipole to a position where its axis is perpendicular to the field is

$2 pE$

$\frac{2 pE}{3}$

$\frac{3 pE}{2}$

$0$

Q. An electric dipole with dipole moment ' p ' is placed with its axis at 30∘ to a uniform electric field. The work done in rotating the dipole to a position where its axis is perpendicular to the field is

2pE

3​2pE​

23​pE​

0

Given, for an electric dipole, θ1​=30∘ θ2​=90∘ ∴ Work done in rotating the dipole from θ1​=30∘ to a position, where its axis is perpendicular (θ2​=90∘) to electric field is given as W=pE(cosθ1​−cosθ2​) =pE(cos30∘−cos90) =pE(23​​−0)=(23​​pE∘)

Q. An electric dipole with dipole moment ' $p$ ' is placed with its axis at $3 0^{\circ}$ to a uniform electric field. The work done in rotating the dipole to a position where its axis is perpendicular to the field is

$2 pE$

$\frac{2 pE}{3}$

$\frac{3 pE}{2}$

$0$