Concepts Of Physics MCQ Edition [Volume 2]
- Exam
- Concepts Of Physics MCQ Edition [Volume 2]
- Subject
- Physics
- Chapter
- Permanent Magnets
Concepts Of Physics MCQ Edition [Volume 2] · Physics · Permanent Magnets
A horizontal circular loop carries a current that appears clockwise...
A horizontal circular loop carries a current that appears clockwise when observed from above. It is substituted by an equivalent magnetic dipole consisting of a south pole and a north pole .
Options
- AThe line must be perpendicular to the plane of the loop
- BThe line must lie along a diameter of the loop
- CThe north pole must be positioned below the loop
- DThe south pole must be positioned below the loop
Correct answer
C. The north pole must be positioned below the loop
Step-by-step solution
According to the right-hand thumb rule, for a circular loop carrying a clockwise current when viewed from above, the magnetic field lines pass through the loop from top to bottom.
This implies that the upper face of the loop acts as a South pole, as magnetic field lines enter it, and the lower face acts as a North pole, as magnetic field lines emerge from it.
When the loop is substituted by an equivalent magnetic dipole, the axis of the dipole, which is the line joining the South pole and the North pole , must align with the magnetic field at the center of the loop. Thus, the line must be perpendicular to the plane of the loop.
The magnetic dipole moment vector points from the South pole to the North pole. Since the magnetic field is directed downwards, the equivalent dipole must be oriented such that its South pole is above the loop and its North pole is below the loop.
This implies that the upper face of the loop acts as a South pole, as magnetic field lines enter it, and the lower face acts as a North pole, as magnetic field lines emerge from it.
When the loop is substituted by an equivalent magnetic dipole, the axis of the dipole, which is the line joining the South pole and the North pole , must align with the magnetic field at the center of the loop. Thus, the line must be perpendicular to the plane of the loop.
The magnetic dipole moment vector points from the South pole to the North pole. Since the magnetic field is directed downwards, the equivalent dipole must be oriented such that its South pole is above the loop and its North pole is below the loop.