Potential Difference across Capacitor.

In summary, the student attempted to find the total energy stored in two capacitors by dividing the voltage between them by the capacitance of each capacitor. However, they were not able to solve for the voltage between the two capacitors, and needed help from the instructor.
  • #1
Aznhmonglor
6
0

Homework Statement



pyweb.jpg




Homework Equations



Not sure which equations to use but I know that we'll have to use the answers from part a and b to answer the questions.



The Attempt at a Solution



What I did was that I said that C1 and the 6 microfarads are parallel to C2 and the 2 microfarads capacitor and said that the voltage would just be halved. Really confused on what to do.
 
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  • #2
remember that voltage is not 'split up' to components in parallel, this only occurs to components in series, which is the second half of the problem
 
  • #3
Chewy0087 said:
remember that voltage is not 'split up' to components in parralel, both the top & the bottom will receive 90V (separateley) and the 90 is shared between the two capacitors.

hmmm thanks that helps to clarify that point. So its 90 volts to C1 and the 6 microfarads capacitor and to the C2 and 2 microfarads capacitor. What equation do I need to use? I have a couple here. Looking at PE=(.5)(C)(deltaV^2) is that the right one? I think the main problem here is that I don't know what equation to use or how to look at the problem.
 
  • #4
hmm I'm afraid not, that's the equation for working out the energy stored in the capacitor, so you'll need it later, however

V = Q / C voltage = charge / capacitance , you know the Q & C for each capacitor, so try to work out V
 
  • #5
Chewy0087 said:
hmm I'm afraid not, that's the equation for working out the energy stored in the capacitor, so you'll need it later, however

V = Q / C voltage = charge / capacitance , you know the Q & C for each capacitor, so try to work out V

hmmm...Im still getting some wrong answers. So let's say for C2, I know the charge on that capacitor is 120 microCouloumbs. I am not sure what the Capacitance for it is. Would the capacitance for C2 be the sum of (1/C1)+(1/C2)=(1/Ctot)? so it would be that V=120/1.5?

Just figured out this part. Now onto the total energy stored by group?

the equation used would be PE=(.5)(C)(deltaV^2) ?
 
Last edited:
  • #6
correcto, but look

let's take C1, you worked out earlier that charge was 120 * 10^-6
and you also know that it's capacitance is 2 * 10^-6 -it tells you on the top of the picture!

so now you have Q and C, and V = Q / C , they seem to work, try them again
 
  • #7
Problem solved!

Thanks a million.
 

What is potential difference across a capacitor?

Potential difference across a capacitor, also known as voltage across a capacitor, is the difference in electric potential between the positive and negative plates of the capacitor. It is measured in volts (V).

How is potential difference across a capacitor calculated?

The potential difference across a capacitor can be calculated by dividing the charge on the capacitor by the capacitance. This can be represented by the equation V = Q/C, where V is the potential difference (in volts), Q is the charge (in coulombs), and C is the capacitance (in farads).

What factors affect the potential difference across a capacitor?

The potential difference across a capacitor can be affected by several factors, including the charge on the capacitor, the capacitance of the capacitor, and the distance between the plates of the capacitor. Additionally, the material and geometry of the capacitor can also play a role in determining the potential difference.

How does potential difference across a capacitor differ from potential difference across other components?

Potential difference across a capacitor is unique from potential difference across other components because a capacitor can store and release charge, while other components such as resistors and inductors do not have this ability. This means that the potential difference across a capacitor can change over time as the capacitor charges and discharges.

What is the significance of potential difference across a capacitor in electronic circuits?

Potential difference across a capacitor is an important factor in electronic circuits as it can determine the amount of charge stored in the capacitor, which can impact the overall behavior and function of the circuit. Additionally, potential difference across a capacitor can also affect the flow of current in the circuit, as the capacitor can act as a barrier or reservoir for charge.

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