Need to find the charge of this capacitor?

In summary, the conversation discusses solving for the charge on capacitor C2 using the loop rule and equations for capacitance. The correct answer is 5 uC, and the mistake in the solution is corrected by adjusting the equation for the loop rule.
  • #1
letsgo
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0

Homework Statement


Given,

MTDnC.png


What is the charge on C2 (the highlighted capacitor).
The answer is supposed to be Q2 = 5 uC


Homework Equations


C=Q/V
Loop Rule?


The Attempt at a Solution


What I did, is using the loop rule on the smaller loop, I set up
V2 - V3 - Vof C2 = 0
6 V - 4 V = Vof C2
2 V = Vof C2

So since,
Vof C2 = Q2/C2

Then,
Q2 = (2 V)(5.0 uF)

And Q = 1.0x10-5 C, however that isn't the answer... It's supposed to be 5 uC.

Solution
Wow, I just figured it out, stupid mistake. It should be V2 + V3 - Vof C2 = 0. That fixes it.
 
Last edited:
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  • #2
Well done - sometimes telling it so someone else focusses your mind and you see what went wrong.
 

1. How do I calculate the charge of a capacitor?

The charge of a capacitor can be calculated by multiplying the capacitance (C) of the capacitor by the voltage (V) across it. In formula form, it is Q = CV.

2. What is the unit of measurement for charge on a capacitor?

The unit of measurement for charge on a capacitor is coulombs (C).

3. Why is it important to know the charge of a capacitor?

Knowing the charge of a capacitor is important because it determines the amount of energy stored in the capacitor. This is crucial information for designing electrical circuits and determining the capacitor's behavior in a circuit.

4. Can the charge of a capacitor be negative?

Yes, the charge on a capacitor can be negative. This occurs when the capacitor is connected in a circuit in such a way that the voltage across it is reversed.

5. How does the charge of a capacitor change over time?

The charge of a capacitor changes over time according to the equation Q = Q0(1-e-t/RC), where Q0 is the initial charge, t is time, R is the resistance in the circuit, and C is the capacitance of the capacitor. In simple terms, the charge on a capacitor increases as it is charged and decreases as it is discharged.

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