# Homework Help: Voltage and energy in capacator system

1. May 13, 2013

### barryj

1. The problem statement, all variables and given/known data
There are two capacitors, 1 farad each, connected by a switch. The initial voltage of one capacitor is 1 volt. At t0, the switch is closed.

What is the system energy before closing the switch
What is the system energy, of both capacitors after closing the switch.
What is the difference in stored energy and why.

2. Relevant equations

V = Q/C

E = (1/2)CV^2

3. The attempt at a solution

initial energy = (1/2) (1) (1)^2 = 1/2 J
Q = CV = (1)(1) = 1 c

After switch closes, the charge is distributed over both capacitors, so each capacitor has a charge of 1/2 c
voltage is Q/C = 1/2 / 1 = 1/2 V
Energy in each cap is (1/2) (1) (1/2)^2 = 1/8
Total stored energy is 1/2 + 1/8 = 1/4

I lost 1/4 J of energy ??
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

#### Attached Files:

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2. May 13, 2013

### Staff: Mentor

Yes, yes you did.

3. May 13, 2013

### barryj

So, where did it go?

4. May 13, 2013

### Staff: Mentor

Can you think of any plausible mechanisms for removing/dissipating the energy?

5. May 13, 2013