# How many will succeed?

Electrically charged drops of mercury fall from an altitude $$h$$ into a spherical metal vessel of radius $$R$$ in the upper part of which there is a small opening. The mass of each drop is $$m$$ and the charge of the drop is $$q$$. The number $$n$$ of the last drop that can still enter the sphere is $$\large n*2\pi \epsilon_0 \frac{mg(h-R)R}{q^2}$$. Then what is the value of $$n$$?

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