The difference between true north and magnetic north is called what?

• A. Variation
• B. Deviation
• C. Declination
• D. Bearing error

Answer: (A)

The concept being tested is the angular difference between true north (geographic north) and magnetic north as it appears on maps and compasses. This offset is what navigators call variation. It’s the amount by which magnetic north diverges from true north at a given location, and it can be east or west depending on where you are.

Variation is the best term here because it specifically refers to that charted offset used to convert between magnetic bearings and true bearings. When using a compass, you adjust by the variation to get an accurate true heading. If the variation is east, you add it to a magnetic bearing; if it’s west, you subtract it. That practical use is why variation is the correct choice for describing the difference between true north and magnetic north in this context. Deviation, by contrast, describes errors caused by a vessel’s own magnetic field affecting the compass, not the difference between north references. Declination is another term you may encounter, but this item is framed to emphasize variation. Bearing error isn’t a standard term for this concept.