Which component of the magnetic field has an effect on the magnetic compass?

The magnetic compass primarily responds to the magnetic field's horizontal component, which is responsible for indicating direction. However, the vertical component also plays a significant role, particularly in areas where the magnetic field's inclination changes.

In practice, while the horizontal component dictates the compass's directional reading during normal use, the vertical component can influence the accuracy and behavior of the compass, especially as you move closer to magnetic poles or in regions with significant variations in the Earth's magnetic field. The vertical component can cause deviations or errors due to the tilt of the compass needle, which can affect navigation.

Therefore, acknowledging that both components interact with the compass is essential for understanding how to effectively use magnetic navigation tools in varying locations.