A composite parallel plate capacitor is made up of two different dielectric materials with different thickness ( t 1 and t 2 ) as shown in figure. The two different dielectric material are separated by a conducting foil F . The voltage of the conducting foil is _____ V .

Step-by-step solution

Capacitance of each capacitor C 1 = A 3 ε 0 1 2 = 6   A ϵ 0 and C 2 = A 4 ϵ 0 1 = 4 A ε 0 Here, A is area of plate. Equivalent capacitance is C eq = C 1 C 2 C 1 + C 2 = 6 A ε 0 × 4 A ε 0 6 A ε 0 + 4 A ε 0 = 24 10 A ϵ 0 Now, net charge stored is q net = C eq ΔV = 24 10 A ε 0 100 = 240 A ε 0 Potential drop across C 2 is Δ V 2 = 240 A ε 0 4 A ε 0 = 60   V Thus, voltage of the conducting foil is V foil   = 60   V