Question

Electric dipole is placed in a uniform electriceld with the dipole axis making an angle theta with the direction of electric field . the orientation of the dipole for stable equilibrium is

Answer 1

for stable equilibrium the electric dipole must make 0 degree with uniform electric field

Answer 2

Answer:

Dipole must form an angle of $0^o$ with the external eletric field for it to be in stable equilibrium.

Explanation:

The potential energy of a dipole in an external electric field is given by the formula,

$U=\vec p.\vec E$

$U=pEcos(\theta)$

Where, $\vec p$ is the dipole vector,

$\vec E$ is the electric field vector,

and $\theta$ is the angle between diople and the external electric field.

The torque due to external electric field on a dipole is given by the formula,

$\tau = -\vec p\times \vec E$

$\tau = -pEsin(\theta)$

For stable equilibrium, the potential energy of the dipole should be minimum and there should be no torque acting on it.

This is possible only for the case when : $\theta = 0^o$

Potential energy of dipole: $U = -p.E.cos(0)=-p.E$      [minimum]

Torques on the dipole: $\tau = p.E.sin(0) = 0$      [No torue acts on dipole]

Therefore, Dipole must form an angle of $0^o$ with the external eletric field for it to be in stable equilibrium.

#SPJ2