Question

Two capacitors of capacitance C are connected in series. If one of them is filled with dielectric substance k, what is the effective capacitance?

• A. $\frac{kC}{(1+k)}$
• B. C(k+1)
• C. $\frac{2kC}{1+k}$
• D. none of these

Answer 1

Answer: (A)

$\frac{kC}{(1+k)}$

When capacitance filled with dielectric , the capacitance becomes $C^{\prime }=kC$
As they are in series so effective capacitance is $C_{ef}=\frac{C{C}^{\prime }}{C+C^{\prime }}=\frac{C\left(kC\right)}{C+kC}=\frac{kC}{1+k}$