Suppose the following situation:
A positively-charged plate, not connected to any e.m.f. source, is brought near a neutral block of conductor material. Naturally, negative charges are induced on the side of the conductor material that is closer to the plate.
I would like to ask what is the change to the potential of this positively-charged plate due to the induced negative charges on the conductor material.
My physics teacher has been trying to convince me that the plate's positive potential decreases as he tells me that the electric field created by the induced negative charges causes the potential of everything in its vicinity to be lowered.
However, I intuitively thought that the potential of the positively-charged plate should increase since the induced negative charges would repel negatively-charged particles in the plate and cause the side of the plate closer to the induced negative charges to become more positively-charged, increasing its positive potential.