# Sustaining a current in conductor placed in external electric field

Consider the following arrangement-

We have a conducting sphere and a positively charged infinite sheet on the left. The field creates induced charges and the net electric field inside the conductor is zero after a very short time. During this short time, there is a current in the conductor as electrons as dragged opposite to the external electric field.

My teacher says that if we want to sustain this brief current we should connect it with a conducting wire making a closed loop. The electrons will flow anticlockwise giving a steady current, which I think is wrong.

When we connect the conducting wire, the sphere and the wire become one complete metal and after a short time again, there will be induced charges in this big metal and electrostatic condition will be reached. The potential inside will be the same everywhere so how will the current flow in a closed loop?

• Your teacher is wrong. Even if there weren't induced charges in the wire, the electric field produced by the charges opposes any electric field created by the plate.
– gmz
Oct 6, 2021 at 6:47
• As @gmz already said, your teacher is wrong. If it were the case, you could build a perpetual motion machine with it. Oct 6, 2021 at 8:51
• What if both the sphere and the wire are superconducting? Why should the induced current stop after a short (or long, given zero resistivity) time? Oct 13, 2021 at 10:40
• Oh no, you need to get a new teacher... Oct 13, 2021 at 21:02