Find out the following if A is connected with C and B is connected with D.
(i) How much charge flows in the circuit.
(ii) How much heat is produced in the circuit.

Explanation

(i)

Let potential of B and D is zero and common potential on capacitors is V, then at A and C it will be V.
By charge conservation, 3V +2V = 40+30
5V=70
V=14 volt
Charge flow = 40-28`=12 mu C`
Now final charges on each plate is shown in the figure
(ii) Heat produced `=(1)/(2)xx2xx(20)^(2)+(1)/(2)xx3xx(10)^(2)-(1)/(2)xx5xx(14)^(2)`

`=400+150-490=550-490=60 mu J`
Note : (i) When capacitor plates are joined then the charge remains conserved.
(ii) We can also use direct formula of redistribution as given above.