Class 12th Physics 2017 Set1 Delhi Board Paper Solution
(i) Find equivalent capacitance between A and B in the combination given below. Each capacitor is of 2 µF capacitance.
(ii) If a DC source of 7V is connected across AB, how much charge is drawn from the source and what is the energy stored in the network?
(i) The given circuit can be redraw as follows:
Here, C2, C3 and C4 are connected in parallel, their equivalent capacitance is:
Ceq = C2 + C3 + C4 = 2+2+2 = 6 µF
Ceq C1 And C5 are in series
So, 1 / C'eq = 1/Ceq +1/C1 + 1/C5 = 1/6 + 1/2 + 1/2 = 7/6 µF
C'eq = 6/7 µF
(ii) Charge down from the source is given by
Q = CV
= 6/7 x 10-6 x 7 = 6 x 10-6C
E = 1/2 CV2
= 1/2 x (6 x 10-6 / 7) x 49
= 21 x 10-6 J.
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