The classic image problem is that of a point charge $q$ held a distance $d$ above a grounded plane. The solution is this problem is to replace grounded plane by a charge $-q$ a distance $d$ below the plane, see the figure (taken from Wikipedia)

enter image description here

With this substitution it is then straightforward to work out that the force of attraction between the charge $q$ and the plane is $$\frac{q^2}{ 4 \pi \epsilon_0 (2d)^2}.$$

If you release the charge $q$, the force acting upon it causes it to accelerate towards the plate, the force varying as $1/d^{2}$. Presumably, this energy gained by the charge comes from the work done keeping the plate grounded. It is obviously not an electro$static$ problem any more and em radiation will also be called into play. But, whatever, you can't physically supply an infinite amount of energy, so what eventually happens?


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