What term describes the angular difference between true north and magnetic north?

• A. Difference between true north and grid north
• B. Angle between magnetic north and true north
• C. Difference between true north and magnetic north
• D. Time variation of magnetic declination

Answer: (C)

The concept being tested is the angular difference between true north and magnetic north, which is magnetic declination (also called variation). This is the specific angle you’d use to adjust a compass so its readings align with true bearings on a map.

The best way to describe that quantity is the difference between true north and magnetic north, because it directly names the amount of directional separation between the two reference norths. Grid north is a different reference used on maps, not the angle between true and magnetic north. The idea of time variation describes how that angle can change over years, but it isn’t the current angular difference itself. Saying the angle between magnetic north and true north gets at the same concept, but the standard term for the quantity is the difference between true north and magnetic north, which is why this phrasing is the most precise.