Calculate the magnitude of the torque acting on the dipole.
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7/8/2015
CBSE
An electric dipole with dipole moment 4 � 10^{−9} C m is aligned at
30� with the direction of a uniform electric field of magnitude 5 � 10^{4}N
C^{−1}. Calculate the magnitude of the torque acting on the dipole.
Answer
Electric dipole moment, p = 4 � 10^{−9} C m (Given)
Angle made by p with a uniform electric field, θ = 30� (Given)
Electric field, E = 5 � 10^{4} N C^{−1} (Given)
Torque acting on the dipole is given by the relation,
������� τ =�pE�sinθ
= 4 � 10^{9} � 5 � 10^{4} � sin 30^{o}
= 20 � 10^{5} � 1/2
= 10^{4} Nm
Therefore, the magnitude of the torque acting on the dipole is 10^{−4}�N
m.