Consider the situation shown in problem E11T. 1 (before charges have time to pile up at the bar's ends).

-(b) There is a magnetic field in the bar's rest frame.

Question

Consider the situation shown in problem E11T. 1 (before charges have time to pile up at the bar's ends).
 
-(b) There is a magnetic field in the bar's rest frame.

Quizplus · Accepted Answer

In the bar's rest frame, the bar is stationary and the charges within it are moving. According to the theory of special relativity, moving charges create a magnetic field. Therefore, there is a magnetic field in the bar's rest frame.

Consider the Situation Shown in Problem E11T