A plate of a 2 microFarad capacitor charged to 100V is connected by a fine wire to a plate of a 0.01 microFarad charged to 200V, the other plates of the two capacitors being joined together and connected to earth. How much charge passes along the wire and how much energy disappears.
The answer to the energy is 1.796E-4
I assumed that the circuit is basically two capacitors in series with no voltage source.
My first attempt was simply adding the energy in both capacitors, E = 1/2 (C1V1^2 + C2V2^2) = 1/2 (2u*100^2 + 0.01u*200^2) = 0.0102J, did not get the correct answer
I then took the series equivalent capacitance, C = 9.95 nF, then used the formula E = 1/2 (CV^2) again, but assuming that there is only a 100V potential difference across the circuit, E = 1/2 (9.95n * 100^2) = 4.975E-5 Joules, still didn't get the correct answer. Tried it with other values for V = 200V and 300V and still couldn't get the answer. What am I doing wrong?
The answer to the energy is 1.796E-4
I assumed that the circuit is basically two capacitors in series with no voltage source.
My first attempt was simply adding the energy in both capacitors, E = 1/2 (C1V1^2 + C2V2^2) = 1/2 (2u*100^2 + 0.01u*200^2) = 0.0102J, did not get the correct answer
I then took the series equivalent capacitance, C = 9.95 nF, then used the formula E = 1/2 (CV^2) again, but assuming that there is only a 100V potential difference across the circuit, E = 1/2 (9.95n * 100^2) = 4.975E-5 Joules, still didn't get the correct answer. Tried it with other values for V = 200V and 300V and still couldn't get the answer. What am I doing wrong?