A parallel plate capacitor has plate area 40 cm 2 and plates separation 2 mm . The space between the plates is filled with a dielectric medium of a thickness 1 mm and dielectric constant 5 . The capacitance of the system is:

Step-by-step solution

With insertion of dielectric, the system can be considered as combination of two capacitors in series. Thus, equivalent capacitance of the system is 1 C eq = 1 C 1 + 1 C 2 = 1 K ε 0   A t + 1 ε 0   A   d - t = t K ε 0   A + d - t ε 0   A = 1 × 10 - 3 5 ε 0 × 40 × 10 - 4 + 1 × 10 - 3 ε 0 × 40 × 10 - 4 ⇒ 1 C eq = 1 20 ε 0 + 1 4 ε 0 ⇒ C eq = 20 × 4 ε 0 24 = 10 ε 0 3   F .