Calculating Charge on Second Capacitor Connected to Battery

In summary, we have a capacitor of C1 = 10 F that builds up a charge of 100 C when connected to a battery. After discharging and connecting a second capacitor of C2 = 20 F in parallel, the two capacitors are connected to the same battery. Using the formula Q = CV, we can find the voltage of the battery to be 10V. Then, using this voltage in the equation U=CV, we can find the energy or charge on the plates of the second capacitor.
  • #1
santina91
2
0
A capacitor of C1 = 10 F is connected to a battery, and a charge of 100 C builds up on the capacitor. Then, the battery is disconnected, the capacitor is discharged, and a second capacitor of capacity C2 = 20 F is connected to it in parallel. Then, the two capacitors are connected to the same battery. What is the charge on the plates (in C) of the second capacitor at that time?



Q=CV
C1+C2=C
t=RC
q=Q0e^(-t/T)



So far the only thing I have come up with to do is find the voltage of the battery by doing 100=10V. That would mean the battery is 10V, but I do not know if this is right or what to do next.
 
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  • #2
note: it is all microcolumbs and microfarrhads
 
  • #3
santina91 said:
note: it is all microcolumbs and microfarrhads

First of all - please. farads after Michael Faraday.

Second of all here's a μ to help you.

As to the capacitors I think all they want is for you to figure the battery voltage and then figure the charge on the second capacitor.
 
Last edited:
  • #4
This problem is much easier than you're making it.
You have the formula Q = CV. You don't know what V is but you know it is constant.
C2 is twice as large as C1.
What happens to Q in the equation if you double the value of C and keep V constant?
 
  • #5
just remember that U=CV
from the givens you found that teh voltage of the battery was 10V
now all you have to do is use that voltage in the equation to find the energy of the second capacitor.
 

1. How do I calculate the charge on a second capacitor connected to a battery?

To calculate the charge on the second capacitor connected to a battery, you will need to use the formula Q = CV, where Q is the charge, C is the capacitance of the capacitor, and V is the voltage of the battery. Make sure to use the values for the second capacitor, not the first one connected to the battery.

2. What is the formula for capacitance?

The formula for capacitance is C = Q/V, where C is the capacitance, Q is the charge, and V is the voltage. This formula shows the relationship between the charge and voltage of a capacitor.

3. Can the charge on a capacitor be negative?

Yes, the charge on a capacitor can be negative. This can happen if the capacitor is connected in reverse polarity, or if the voltage across the capacitor is reversed. In these cases, the charge on the capacitor will be negative and will flow in the opposite direction.

4. How does the charge on a second capacitor affect the overall charge on the battery?

The charge on a second capacitor connected to a battery does not affect the overall charge on the battery. The total charge on the battery remains the same, but it is distributed between the two capacitors based on their capacitance values.

5. Is there a limit to the charge that can be stored on a capacitor?

Yes, there is a limit to the charge that can be stored on a capacitor. This limit is determined by the capacitance and voltage of the capacitor. The higher the capacitance and voltage, the higher the maximum charge that can be stored. Going beyond this limit can damage the capacitor or cause it to fail.

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