Earth’s magnetic dipole axis is tilted approximately relative to the planet’s…
PHYSICS · Multi-part · CBSE · Physics · Electricity: Magnetic and Heating Effects · Electricity: Magnetic and Heating Effects
Problem
Earth’s magnetic dipole axis is tilted approximately 11∘ relative to the planet’s geographic (rotational) axis. Assume the magnetic south pole lies near the geographic north pole so that field lines at Earth’s surface generally enter the planet in the northern hemisphere and exit in the southern hemisphere. A lightweight, freely pivoting compass needle is carried to various locations around the globe.
(a) Describe how the direction of the local magnetic field at the geographic North Pole differs from that at the geographic equator. Include both horizontal and vertical components in your discussion.
(b) Explain why a compass needle located exactly at the geographic North Pole cannot be used to identify directions in the horizontal plane.
(c) A navigator at latitude 45∘ N notices that the compass needle is not perfectly horizontal. Qualitatively explain the physical reason for this observation and state whether the north–seeking end of the needle tilts upward or downward.
(d) Discuss two practical implications of the tilt and declination of Earth’s magnetic field for long-distance surface navigation systems (such as ships or hiking expeditions).