where Es is the
remarkable observation is that this experiment can be done with or without
electrostatic shielding around the conductor. It is worth noting that
the Em field is quite different from the Es field in that the
boundary condition for Em is equal to the boundary conditions for the
magnetic field. (More on this later.)
In the equilibrium state, the observer in
the reference frame of the moving rod will not feel any forces due to
electric fields, either Es or Em. This conclusion has
some profound effects on our experiments. For example, one cannot
connect a voltmeter to the moving rod (that is stationary with respect to
the rod) and expect to see a motional electric potential, Em.
All wires of the voltmeter and the voltmeter itself will be equally
polarized, in a manner similar to the rod. Understanding this concept
is important, as it may be one of the fundamental reasons why the motional
electric field often goes undetected.