Which statement is true about magnetic circuits?

Which statement is true about magnetic circuits?

• A. Magnetic lines of force form a closed loop called a magnetic circuit.
• B. Magnetic lines of force form an open circuit.
• C. Magnetic lines of force exist only in copper wires.
• D. Magnetic lines of force cannot be measured.

Answer: (A)

Magnetic flux always forms closed loops because there are no magnetic monopoles; the flux is driven through a defined path and must return to complete the loop. In a magnetic circuit, the flux travels through the magnetic path—such as a core and any gaps—and completes the loop back to the starting region, much like current in an electric circuit finding a continuous path. This closed-loop nature is why we describe the system as a magnetic circuit: it has a path with reluctance and is driven by magnetomotive force, organizing how flux flows. The other statements don’t fit because lines of force do not form an open circuit, they are not confined to copper wires, and they can be measured or visualized with appropriate instruments.

Magnetic flux always forms closed loops because there are no magnetic monopoles; the flux is driven through a defined path and must return to complete the loop. In a magnetic circuit, the flux travels through the magnetic path—such as a core and any gaps—and completes the loop back to the starting region, much like current in an electric circuit finding a continuous path. This closed-loop nature is why we describe the system as a magnetic circuit: it has a path with reluctance and is driven by magnetomotive force, organizing how flux flows.

The other statements don’t fit because lines of force do not form an open circuit, they are not confined to copper wires, and they can be measured or visualized with appropriate instruments.