Question

Two cells, two resistors and two capacitors are connected as shown in figure. The charge on $2\mu F$ capacitor is :

• A. $30\mu C$
• B. $25\mu C$
• C. $20\mu C$
• D. $48\mu C$

Answer 1

Answer: (A)

When the capacitor is fully charged , the current only flow through the resistors in this circuit.

As the two capacitors are charged by two different emf so they connected in series so charge of them is equal .i.e, q (say).

Apply Kirchhoff's law,

for loop AEHDA: $18=(1+5)i_1\Rightarrow i_1=3A$

for loop BCGFB: $15=(2+4)i_2\Rightarrow i_2=2.5A$

for loop ABCDA: $18+15=q/3+2i_2+q/2+1i_1$

or $33=\left(5/6\right)q+2\left(2.5\right)+1\left(3\right)=\left(5/6\right)q+8$

or $q=25\times \left(6/5\right)=30\mu C$