After landing on an unexplored Klingon planet, Spock tests for the direction of the magnetic field by firing a beam of electrons in various directions and by recording the following observations:
Electrons moving upward feel a magnetic force in the northwest direction.
Electrons moving horizontally toward the north are pushed downward.
Electrons moving horizontally toward the southeast are pushed upward.
Mr) Spock therefore concludes that the magnetic field at this landing site is in which direction?
A) toward the southeast
B) toward the west
C) toward the east
D) toward the northeast
E) toward the southwest

Question

Quizplus · Accepted Answer

The direction of the magnetic force on moving charges (electrons in this case) can be determined using the right-hand rule. Given the observations:1. Electrons moving upward feeling a force toward the northwest implies the magnetic field is perpendicular to both the direction of motion (upward) and the force (northwest), suggesting a southwest to northeast direction.2. Electrons moving north being pushed downward further supports that the magnetic field is oriented from southwest to northeast, as a field in this direction would indeed push north-moving electrons downward.3. Electrons moving southeast and being pushed upward also align with a magnetic field directed from southwest to northeast, as this would cause a perpendicular upward force on southeast-moving electrons.Thus, the magnetic field direction that aligns with all observations is toward the southwest.

After Landing on an Unexplored Klingon Planet, Spock Tests for the Direction