Question

what is the formula for finding the heat produced in capacitor?

Answer 1

ere's how I go:

Since there's no current in both states, we can disregard the resistor.

I calculate voltage of C1, when switch is open

U=Q/C=2VU=Q/C=2V

Switch closes, voltage is

E1−E2=8VE1−E2=8V

it divides on capacitors 4/3V on C1 and 20/3 on C2.

Use

We=1/2∗C∗(ΔU)2We=1/2∗C∗(ΔU)2

Use it on both capacitors, sum them and get the wrong result, 70/3 instead of 15μJ.

Answer 2

Answer:

Since there's no current in both states, we can disregard the resistor.

I calculate voltage of C1, when switch is open

U=Q/C=2VU=Q/C=2V

Switch closes, voltage is

E1−E2=8VE1−E2=8V

it divides on capacitors 4/3V on C1 and 20/3 on C2.

Use

We=1/2∗C∗(ΔU)2We=1/2∗C∗(ΔU)2

Use it on both capacitors, sum them and get the wrong result, 70/3 instead of 15μJ.

I hope this helps.