In outer space, you observe a straight stream of electrons flowing past you at 14.5 miles per second, about the same speed that Mars moves on its orbit around the sun. You maneuver your spacecraft to face the current so that the electrons are moving from left to right and so that you are 10 m from the stream. Now you fire your rockets and boost your speed so that you are also moving at 14.5 miles per second, exactly at the same speed and direction as the electrons. In what direction does a compass needle point now?
A) up
B) down
C) left
D) right
E) You observe no magnetic field.

Question

In outer space, you observe a straight stream of electrons flowing past you at 14.5 miles per second, about the same speed that Mars moves on its orbit around the sun.  You maneuver your spacecraft to face the current so that the electrons are moving from left to right and so that you are 10 m from the stream. Now you fire your rockets and boost your speed so that you are also moving at 14.5 miles per second, exactly at the same speed and direction as the electrons. In what direction does a compass needle point now?
A) up 
B) down 
C) left 
D) right 
E) You observe no magnetic field.

Quizplus · Accepted Answer

A compass needle points towards the magnetic north pole, which is caused by the Earth's magnetic field. The presence of a magnetic field would cause the compass to point in a particular direction, but since the question states that no magnetic field is observed, the correct answer is E.

In Outer Space, You Observe a Straight Stream of Electrons