Electric Charges and Fields Test 9

Ionic behavior implies dipole moment.

HCl is an ionic compound (H⁺Cl^-)
CO₂, CH₄ and BF₃  is a covalent compound

Stable equilibrium is attained when potential energy of the dipole system is minimum which is possible at an inclination of 0°.

On equatorial line, the direction of electric field is reversed to that of angle of axial line. Therefore, the angle between dipole moment and electric field is 180°.

An electric dipole is a separation of positive and negative charges. The simplest example of this is a pair of electric charges of equal magnitude but opposite sign, separated by some (usually small) distance. A permanent electric dipole is called an electret.

Electric Field Intensity due to a short dipole is given by

E = K2P/r^3

where K is the proportionality constant

P is the electric dipole moment

So electric field intensity is inversely proportional to r^3

q= 4μc = 4 x 10^-6c
2l = 5mm = 5 x 10^-3m
Dipole moment  P = q.2l
= 4 x 10^-6 x 5 x 10^-3
= 20 x 10^-9
= 2 x 10 x 10^-9
= 2 x 10^-8 c.m 

its direction is toward the positive charge.

Electric flux is a scalar quantity. It is a scalar because it is the dot product of two vector quantities, electric field and the perpendicular differential area.

By definition of Electric Dipole

+Q charge is moving on equatorial line of dipole as shown in figure, since on equatorial line V=0,
Hence the potential difference is zero. So, W=0

Torque on a dipole kept in external electric field is given by the expression,