Electric Dipoles

Author:Asok Kumar Das & Chittaranjan Dasgupta
12th West Bengal Board
IMPORTANT

Important Questions on Electric Dipoles

EASY
IMPORTANT

How much work will be done by an external agent to turn an electric dipole of moment P through 

(ii) 180° (end-for-end) and 360° from the direction of the electric field ?

MEDIUM
IMPORTANT

How much work will be done by an external agent to turn an electric dipole of moment P through 

(i) 90° (end-for-end) and 360° from the direction of the electric field?

EASY
IMPORTANT

Show mathematically that the potential at a point on the equatorial line in an electric dipole is zero.

EASY
IMPORTANT

Which orientation of an electric dipole is a uniform electric field would correspond to stable equilibrium ?

EASY
IMPORTANT

Electric dipole moment is equal to the product of the magnitude of either charge of the dipole and the distance between the charges.

EASY
IMPORTANT

What is the energy in electron-volt of a photo-electron moving with velocity 2×107 m/s ? Given mass of electron =9.1×10-28 gm.

EASY
IMPORTANT

The distance of the field point, on the equatorial plane of a small electric dipole, is halved. By what factor will the electric field, due to the dipole change ?

EASY
IMPORTANT

Give the dependence of electrostatic potential due to a small electric dipole at a far off point lying on (i) the axial line

(ii) the equatorial line.

EASY
IMPORTANT

Give the dependence of electrostatic potential due to a small electric dipole at a far off point lying on 

(i) the axial line,

EASY
IMPORTANT

An electric dipole is formed by two charges q and -q placed at the two ends of an insulating rod of length d and negligible mass. Write down the dipole moment. Is it a vector or a scalar?

MEDIUM
IMPORTANT

Two electric dipoles, each of dipole moment p are placed at right angle to each other at the origin, one along the X -axis and the other along the Y -axis. Find the electric field at a distance r from the origin in a direction making an angle θ with the X axis.

HARD
IMPORTANT

A freely suspended electric dipole is found to oscillate about its equilibrium position with a frequency 31.83 Hz. Find the strength of the electric field. Given : moment of the dipole is 2×10-11 cm and moment of inertia of the dipole about its centre of mass is 3×10-10kgm2.   

EASY
IMPORTANT

Find the binding energy of a dipole consisting of two charges 5μC and -5μC separated by a distance 25μ micron 

MEDIUM
IMPORTANT

A dipole of moment p=10-8(5i^+j^-2k^)cm   is placed in E=108(i^+j^+k^)Vm-1. Find the torque acting on the dipole?

EASY
IMPORTANT

An electric dipole is placed at an angle of 30° to a nonuniform electric field. The dipole will experience

HARD
IMPORTANT

An electric dipole of length 2 cm is placed with its axis making an angle of 60° to a uniform electric field of 105 N/C. If it experiences a torque of 83Nm Calculate the magnitude of the charge on the dipole and potential energy of the dipole.

MEDIUM
IMPORTANT

An electric dipole of length 4 cm, when placed with its axis making an angle of 60° with a uniform field experiences a torque of 43Nm. Calculate the potential energy of the dipole, if the dipole has charges of ±8nC

HARD
IMPORTANT

An electric dipole of length 4 cm, when placed with its axis making an angle of 60° with a uniform field experiences a torque of 43Nm Calculate the

(i) magnitude of the electric field 

HARD
IMPORTANT

An electric dipole of moment 4×10-10 cm is placed in a uniform electric field of intensity 10×106 V/m. Find its maximum and minimum potential energy.