Two-point charges q 1 and q 2 are located at are located at r 1 → and r 2 → , respectively in an external electric field E → . Obtain the expression for the total work done in assembling this configuration.

Given that two-point charges q 1 and q 2 are located at r 1 → and r 2 → , respectively in an external electric field E → . Let V r 1 → and V r 2 → be the electric potentials of the field E → at the points having position vectors r 1 → and r 2 → . The work done in bringing the charge q 1 from infinity to point A is given by, Work done on q 1 against the external field is q 2 V r 1 → Work done in bringing q 2 from ∞ to r 2 → against the external field = q 2 V r 2 → Work done on q 2 against the force exerted by q 1 = 1 4 π ε 0 . q 1 q 2 r 12 Where r 12 is the distance between q 1 and q 2 . Total work done is q 1 V r 1 → + q 2 V r 2 → + 1 4 π ε 0 . q 1 q 2 r 12

An electric dipole is held in a uniform electric field E → . Show that the net force acting on it is zero.

Consider an electric dipole consisting of charges + q and - q and of length 2 a placed in a uniform electric field E → making an angle θ with it. It has a dipole moment of magnitude, p = q × 2 a Force exerted on charge + q by field E → = q E → (along E → ) Force exerted on charge - q by field E → = - q E → (opposite to E → ) F → T o t a l = - q E → - q E → = 0

An electric dipole is held in a uniform electric field E → . The dipole is aligned with its dipole moment p → parallel to the field E → . Find the work done in turning the dipole till its dipole moment points in the direction opposite to E → .

W = ∫ 0 π τ d θ = ∫ 0 π p E s i n θ = p E [ - cos θ ] 0 π = - 2 p E

An electric dipole is held in a uniform electric field E → . The dipole is aligned with its dipole moment p → parallel to the field E → . Find the orientation of the dipole for which the torque acting on it becomes maximum.

As τ = p E sin θ , so τ is maximum when θ = 90 o .

EASY

12th CBSE

IMPORTANT

Earn 100

Draw the equipotential surfaces due to an electric dipole. Locate the points where the potential due to the dipole is zero.

Important Questions on Electrostatic Potential and Capacitance

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 2 - Electrostatic Potential and Capacitance>Text Based Exercises>Q 19

Two-point charges

q_{1}

and

q_{2}

are located at are located at

\vec{r_{1}}

and

\vec{r_{2}}

, respectively in an external electric field

\vec{E}

. Obtain the expression for the total work done in assembling this configuration.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 2 - Electrostatic Potential and Capacitance>Text Based Exercises>Q 20

Write two properties by which electric potential is related to the electric field.

MEDIUM

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 2 - Electrostatic Potential and Capacitance>Text Based Exercises>Q 20

Two-point charges

q_{1}

and

q_{2}

, separated by a distance of

r_{12}

are kept in an external electric field. Derive an expression for the potential energy of the system of two charges in the field.

MEDIUM

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 2 - Electrostatic Potential and Capacitance>Text Based Exercises>Q 21

Derive an expression for the potential energy of an electric dipole of the dipole moment

\vec{p}

in an electric filed

\vec{E}

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 2 - Electrostatic Potential and Capacitance>Text Based Exercises>Q 22

An electric dipole is held in a uniform electric field

\vec{E}

. Show that the net force acting on it is zero.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 2 - Electrostatic Potential and Capacitance>Text Based Exercises>Q 22

An electric dipole is held in a uniform electric field $\vec{E}$ . The dipole is aligned with its dipole moment $\vec{p}$ parallel to the field $\vec{E}$ . Find the work done in turning the dipole till its dipole moment points in the direction opposite to $\vec{E}$ .

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 2 - Electrostatic Potential and Capacitance>Text Based Exercises>Q 22

An electric dipole is held in a uniform electric field $\vec{E}$ . The dipole is aligned with its dipole moment $\vec{p}$ parallel to the field $\vec{E}$ . Find the orientation of the dipole for which the torque acting on it becomes maximum.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 2 - Electrostatic Potential and Capacitance>Text Based Exercises>Q 23

Using Gauss' law, Show that the electric field inside a conductor is zero.

Draw the equipotential surfaces due to an electric dipole. Locate the points where the potential due to the dipole is zero.

Important Questions on Electrostatic Potential and Capacitance

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