# Energy dissipated

Can someone explain what part E of the question means and how to do it? Thanks!
https://isaacphysics.org/questions/two_capacitor_problem?stage=a_level
Original post by Scarlett L
Can someone explain what part E of the question means and how to do it? Thanks!
https://isaacphysics.org/questions/two_capacitor_problem?stage=a_level

I thought the question was quite clear: in a typical DC circuit (no capacitor) that consists of a switch, a resistor with resistance R and an ideal cell of emf V, the switch is closed for 2 minutes and what is the energy dissipated in the resistor in 2 minutes? Energy dissipated = (V^2/R)*120 J

Returning to Part E, when S1 is opened and S2 is closed, charges on C1 are transferred to C2 and current flows through the resistor R2 for some time, say t1. When the current flows through the resistor R2, energy is dissipated in a time interval of t1 which is what the question is asking.
Next, we can find the energy dissipated in R2, by using the principle of conservation of energy: find the initial energy stored in C1, final energy in C1, final energy in C2 and hence the energy dissipated in R2.
I’ve solve the question now, thank you for your hint!