Question 27

In a certain region of space, electric field is along the z-direction throughout. The magnitude of electric field is, however, not constant but increases uniformly along the positive z-direction, at the rate of 105 NC^{-1 }per metre. What are the force and torque experienced by a system having a total dipole moment equal to 10^{-7} Cm in the negative z-direction?

Answer

Dipole moment of the system, p = q × dl = −10^{−7} C m

Rate of increase of electric field per unit length,

Force (F) experienced by the system is given by the relation,

F = qE

= −10^{−7} × 10^{−5}

= −10^{−2} N

The force is −10^{−2} N in the negative z-direction i.e., opposite to the direction of electric field. Hence, the angle between electric field and dipole moment is 180°.

Torque (τ) is given by the relation,

τ = pE sin180° = 0

Therefore, the torque experienced by the system is zero.

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Sanu
2019-05-19 22:04:10

Thanks

Ekamjeet Singh Grewal
2018-11-03 14:49:39

There's a error in the typing

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