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 east
B)toward the northeast
C)toward the southwest
D)toward the southeast
E)toward the west

Question

Quizplus · Accepted Answer

From the observations, we can conclude that the magnetic field is pointing towards the northwest-southeast direction. When the electrons are moving upward, they feel a force in the northwest direction. When electrons move horizontally towards the north, they are pushed downward. This implies that the magnetic field is perpendicular to the direction of motion and pointing towards the west. Similarly, when electrons move horizontally towards the southeast, they are pushed upward, which also implies that the magnetic field is perpendicular to the direction of motion and pointing towards the west.

Combining these observations, we can infer that the magnetic field is pointing towards the west-northwest direction. Therefore, the best choice is C) toward the southwest, which is the opposite direction of west-northwest.

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