A) 5V
B) 8V
C) 10 V
D) 12V
E) 3V
Correct Answer: C
Solution :
Let capacitance of each capacitor is C. Then equivalent capacitance in series is \[\frac{1}{C}=\frac{1}{C}+\frac{1}{C}=\frac{2}{C}\] \[\Rightarrow \] \[C=\frac{C}{2}\] Charge \[Q=CV=\frac{C}{2}.15\] ...(1) When filled with dielectric \[{{C}_{1}}=4C,{{C}_{2}}=C\] \[\frac{1}{C}=\frac{1}{4C}+\frac{1}{C}=\frac{5}{4C}\] \[\Rightarrow \] \[C=\frac{4C}{5}\] Since, charge is conserved \[Q=CV=\frac{4C}{5}\times V\] ...(2) From Eqs. (1) and (2), we get \[\frac{C}{2}\times 15=\frac{4C}{5}\times V\] \[\Rightarrow \] \[V=\frac{15\times 5}{4\times 2}=9.4V\approx 10V\]You need to login to perform this action.
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