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alexburns1991
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Homework Statement
A 50 [tex]\mu[/tex]F capacitor is being charged from a 6V battery via a 100k[tex]\Omega[/tex] resistor . what is the initial charging current? after a period of time, the charging current is 30[tex]\mu[/tex]A. what are the pd's across the resistor and the capacitor at that moment? how much charge has been stored on the capacitor up to that time?
Homework Equations
Q = CV
Initial Charging Current = emf/resistance
Q = EC (1 - e-t/RC)
The Attempt at a Solution
the initial charging current wasnt a problem, using V=IR.
I0 = 60[tex]\mu[/tex]A
from there on, i struggled to get the pd's but i realized that one half time had gone seeing as the current had halved so the pd must be 3V on each.
i tried using Q = CV to find the charge on the capacitor at that point, but it gave me 1.5 x 10-4C which is not the answer given. i also used the third equation given to get the charge, given the time- but the e term was negative, giving a negative amount of charge. the answer given in the book is 6[tex]\mu[/tex]C, but i can't see how to get this.
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