A ________-shaped coil allows a much stronger field to be created than a flat coil does.

A ________-shaped coil allows a much stronger field to be created than a flat coil does.

• A. Spiral
• B. Circular
• C. Rectangular
• D. Linear

Answer: (A)

A coil gains a stronger magnetic field when more turns are packed into a compact path with the current flowing through each turn in the same direction. A spiral winding does exactly that: many turns are tightly wound in a single, compact fingerprint, so their magnetic fields add up in the same region and reinforce each other. This creates a higher flux density at the center (and higher inductance) for the same current and footprint. With a flat coil (where turns are spread out over a plane or not as densely packed), there are fewer turns in a given area and the individual fields don’t reinforce as effectively in the central region, so the resulting field is weaker. That’s why a spiral-shaped coil can produce a much stronger field than a flat coil of similar size.

A coil gains a stronger magnetic field when more turns are packed into a compact path with the current flowing through each turn in the same direction. A spiral winding does exactly that: many turns are tightly wound in a single, compact fingerprint, so their magnetic fields add up in the same region and reinforce each other. This creates a higher flux density at the center (and higher inductance) for the same current and footprint.

With a flat coil (where turns are spread out over a plane or not as densely packed), there are fewer turns in a given area and the individual fields don’t reinforce as effectively in the central region, so the resulting field is weaker.

That’s why a spiral-shaped coil can produce a much stronger field than a flat coil of similar size.