What is referred to as compass error caused by the difference in physical locations of the magnetic north pole and the geographic north pole?

The term that describes the compass error resulting from the difference in physical locations between the magnetic north pole and the geographic north pole is known as magnetic variation. This phenomenon occurs because a magnetic compass points towards the magnetic north pole, which can be several degrees west or east of true north (the direction of the geographic north pole). This difference is specific to a location and affects navigation; hence, pilots must account for magnetic variation in their flight planning and operations to ensure accurate heading and course.

In aviation, understanding magnetic variation is crucial because it helps pilots correct their compass readings for more precise navigation, particularly in areas where the variation is significant. By knowing the local magnetic variation, pilots can adjust their headings accordingly, ensuring they reach their intended destinations.

Other terms in the choices refer to different phenomena, such as deviation, which is the error caused by magnetic fields within the aircraft itself, and magnetic declination, which is often used interchangeably with magnetic variation but typically refers more specifically to the angular difference. Magnetic dip describes the angle between the horizontal plane and the Earth's magnetic field lines, which does not relate to the difference between the magnetic and geographic poles.