How does a dipole behave when it is placed in a uniform magnetic field?

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  1. It experiences torque but no net force.
  2. It experiences both a net force and torque.
  3. It experiences a net force but no torque.
  4. It remains stationary with no force or torque acting on it.

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Option 1 : It experiences torque but no net force.
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The correct answer is It experiences torque but no net force..

Key Points

  • A dipole in a uniform magnetic field experiences torque due to the interaction between the magnetic field and the magnetic moments.
  • The torque acts to align the dipole with the magnetic field direction.
  • There is no net force acting on the dipole in a uniform magnetic field as the forces on the two poles of the dipole are equal and opposite, canceling each other out.
  • The magnitude of the torque is given by τ = pE sin θ, where p is the dipole moment, E is the electric field, and θ is the angle between p and E.

Additional Information

  • Magnetic Dipole Moment:
    • It is a measure of the strength of a magnetic source.
    • It is a vector quantity with both magnitude and direction.
  • Uniform Magnetic Field:
    • A magnetic field that has the same strength and direction at all points.
    • Examples include the Earth's magnetic field over small regions and the magnetic field inside a solenoid.
  • Torque on a Dipole:
    • Torque is the rotational equivalent of force.
    • It causes the dipole to rotate and align with the magnetic field.
    • The formula for torque is τ = pE sin θ.
  • Electric Dipole:
    • Consists of two equal and opposite charges separated by a distance.
    • It creates an electric field with a characteristic pattern.
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