Question

The next (2) Which dipole experiences the greatest magnitude magnetic torque? (2) Which dipole has the highest magnetic potential energy? д) A b) D (c) E) @c (2) If the dipoles are free to re-orient in direction, which one will not change its direction'?

Answer 1

Torque = IABsin$\theta$

where $\theta$ is the angle between normal vector and field

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3) In this, torque is maximum if $\theta$= 90

the normal (as denoted by arrow) for dipole B is perpendicular to the field, so $\theta$ = 90

sin 90 = 1

so,

Torque = IAB (This is the maximum torque )

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4) The magnetic potential energy is usually expressed in terms of the magnetic dipole moment.

U = -uB

U = -IAB

the negative sign indicates that dipole moment is just opposite to direction of field.

SO, correct option will be dipole C

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5) The dipole will not rotate if $\theta$ = 0 which is true for dipole D