Physics!!!????

Question

Ok so how do you find the number of excess or deficit electrons on a oil drop( ia lready have q, E, Voltage, and diplacement of the Parallel plates).

Thanks.

Answer 1

If the oil drop is suspended between the plates

F(gravity) = F(electric)
mg= EQ where
m - mass of the oil droplet
Q - charge on the oil droplet
E- field intensity
g - acceleration due to gravity

Q= mg/E
number of electrons = Q/q

Answer 2

I assume you are talking about the Millikan Oil Drop Experiment. If you already have q (I'm guessing that's the charge on a drop -- you haven't defined your symbols), just divide by the charge on one electron.

If you are actually doing the experiment you have to measure the charge on a large number of oil drops and plot them to see if they bunch up at multiples of a particular lowest value. That value is your experimental estimate of e.