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Question

Three capacitors (4.0, 6.0, and 8.0 µF) are connected in series across a 50.0-V battery. Find the voltage across the 4.0-µF capacitor.

Answer 1

Ok, when the capacitors are in series, the charge in every capacitor is the same, but the voltage is different.

Let's find the equivalent capacitor :

Ceq when they are on series :

1/Ceq = 1/4 + 1/6 + 1/8

Ceq = 48 /26 (uF)

you know that :

q / Ceq = V

q / (48/26) = 50

q = 92.3 (uF)*(V)

the charge "q" is the same on every capacitor, so for the 4 uF, capacitor :

92.3 (uF)*(V) / 4 (uF) = V

V = 23 Volts

Hope that helped you.