The simulation on the left represents a positive charge (+q) at the position
(x,y)=(d,d) near two infinite grounded conducting sheets. The animation on
the right depicts a similar situation without the conductor present. The
rectangles are there for your reference only.
the animation on the right to place charge(s) where they belong to make the
field on the right match the field on the left for x>0, y>0 (the region
where the +q is located). Assuming you could do this, where are the charge(s)?
There are three charges needed. One +q charge at (x,y)=(–d,-d) and two –q
charges at(x,y)=(d,-d) and (x,y)=(–d,d), respectively. The electric potential
on the conductor will not be zero otherwise. This is another example of the
method of images from electrostatics. Again, the electric field is indeed
different outside of the region of interest. This is a good in class warm up for
the out of class calculation of the electric potential and electric field of
this configuration since the instructor knows the students’ starting point for
Script Author: Mario Belloni