Question 885: Electrostats & Capacitance

Question

An electric dipole having dipole moment $$\mathrm{P}=\mathrm{q} 	imes 2 \ell$$ is placed in a uniform electric field '$$\mathrm{E}$$'. The dipole moment is along the direction of the field. The force acting on it and its potential energy are respectively

Accepted Answer

A dipole has two equal and opposite charges. In a uniform electric field, the two charges will experience equal and opposite force, hence net force will be zero.
The potential energy of an electric dipole is given by
$$U=-p E \cos 	heta$$
where $$	heta$$ is the angle between the dipole moment and the electric field. The potential energy will be minimum when $$\cos 	heta$$ is maximum.
For $$	heta=0^{\circ}, \cos 	heta$$ has maximum value equal to 1.
$$	herefore \mathrm{U}=-\mathrm{pE} 	ext { when } 	heta=0^{\circ} 	ext {. }$$

Answer

$$\mathrm{qE}$$ and minimum

Answer

$$\mathrm{qE}$$ and maximum

Answer

$$2 \mathrm{qE}$$ and minimum

Answer

zero and minimum

Electrostats & Capacitance

An electric dipole having dipole moment $\mathrm{P}=\mathrm{q} \times 2 \ell is placed in a uniform electric field '\mathrm{E}$'. The dipole moment is along the direction of the field. The force acting on it and its potential energy are respectively

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