Electric Dipole

An electric dipole is kept in non-uniform electric field. It experiences

• A force and a torque

• A force but not a torque

• A torque but not a force

• Neither a force nor a torque

An electric

dipole consisting of two opposite charges of 2×10 -6C each separated by a

distance of 3cm is placed in an

electric field of 2×105 N/C. The maximum torque on the dipole will be

• 12×10 ^-1Nm

• 12×10−3Nm

• 24×10−1Nm

• 24×10−3Nm

The distance between the two charges +q and –q of a dipole is r. On the axial line at a distance d from the centre of dipole, the electric field intensity is proportional to

• q/d²

• qr/d²

• q/d³

• qr/d³

If Ea be the

electric field strength of a short dipole at a point on its axial line

and Ee that on the equatorial line at the

same distance, then

• Ee=2Ea

• Ea=2Ee

• Ea=Ee

• None of the above

If the

magnitude of intensity of electric field at a distance x on axial

line and at a distance y on

equatorial line on a given dipole are equal, then x:y is

• 1:1

• 1:√2

• 1:2

• 2√3:1

The electric intensity due to a dipole of length 10 cm and having a charge of 500μC, at a point on the axis at a distance 20 cm from one of the charges in air, is

• 6.25×10^7 N/C

• 9.28×10^7 N/C

• 13.1×11^11N/C

• 20.5×10^7 N/C

What is the angle between the electric dipole moment and the electric field strength due to

it on the equatorial line?

• 0°

• 90°

• 180°

• None of these

An electric dipole is placed in an

electric field generated by a point charge

• The net electric force on the dipole must be zero

• The net electric force on the dipole may be zero

• The torque on the dipole due to the field must be zero

• The torque on the dipole due to the field may be zero

When air is replaced by a dielectric medium of constant K, the maximum force of attraction between two charges separated by a distance

• increases K times

• remains unchanged

• decreases K times

• increases K^-1 times

SI unit of permittivity of free space is

• Farad

• Weber

• C²N^-1 m^-2

• C²N^-1 m^-2