As per question, the figure can be shown for a parallel plate capacitors
Initially, capacitance, C0=
ε0A
d
...(i) where, ε0= permittivity of free space, A= area of plates and d= distance between plates. In presence of a dielectric medium between the plates, the capacitance will be C=
ε0KA
d
...(ii) Also, from the figure capacitors C1 and C2 are in series. ∴ Equivalent capacitance is given by