Question

Two identical electric dipoles, having charge q and dipole length 2d, are kept perpendicular to each other. The net dipole moment of the system will be

Answer 1

Explanation:

The two dipoles are placed at an angle of 120

0

The dipole moment of AB is directed towards B

and that of cd is directed towards c

Hence,

the resultant dipole moment is given as

R=

P

2

+P

2

+2PPcos120

=

2p

2

−

2

2p

2

=p

when the system is subjected to an electric field ,there is a to sque

acting on the dipole.

The field IS directed towards X-axis .The angle COR in the

above diagram will be 60

0

.

Hence,the angle between the resultant dipole moment and electric field

is 90

0

−60

0

=30

0

∴ torque on the system is

τ=PEsinθ=PEsin30=

2

PE

The direction of torque is perpendicular to both P and E