A compass works because its magnetic needle does which of the following?

• A. Aligns itself with Earth's gravitational field
• B. Always points toward geographic north regardless of any magnetic field
• C. Aligns itself with the local magnetic field of Earth
• D. Points in the direction of Earth's rotation due to the Coriolis effect

Answer: (C)

Verified step by step guidance

1. Understand that a compass needle is a small magnet that can rotate freely on a pivot.
2. Recall that magnetic materials experience a torque when placed in a magnetic field, causing them to align with the field lines.
3. Recognize that Earth generates a magnetic field, often approximated as a dipole field with magnetic north and south poles.
4. Know that the compass needle aligns itself along the local magnetic field lines of Earth, pointing toward the magnetic north pole, not the geographic north pole.
5. Conclude that the compass does not respond to Earth's gravitational field or rotation, but specifically to the magnetic field, which is why it points in the direction of Earth's magnetic field.