(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Two parallel plates are placed 0.10 m apart with one vertically above the other and their edges aligned. The potential difference of the upper plate is 100 kV relative to the lower plate. What charge must a spherical raindrop of diameter 1.0 mm carry if it remains suspended between the plates? Assume that the electric field between the plates is uniform and give your answer in units of the charge on an electron. (The density of water is 1000 kg m−3

2. Relevant equations

C = q/V

C = e0 et(A/D)

3. The attempt at a solution

I know that I've got to work out the capacitance in order to work out the charge q=CV but how do I find the capacitance?

I understand Capacitance = permitivity of free space x relative permitivity (Area/Distance of plate separation)

I think I need to find the area and the permitivity but I dont understand why they've given the density of water?

Help please!!!

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# Homework Help: Charge in a capacitor

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