Question

In the circuit diagram shown all the capacitors arein mF. The equivalent capacitance between pointsA & B is (in mF) :++10(1) 14/5(3) 3/7(2) 7.5(4) None of these​

Answer 1

The equivalent capacitance is 19.6 mF

Explanation:

The capacitors with capacitance are

C1 = 6   C2 = 8  C3 = 10  C4 = 3  C5 = 4 and C6 = 7

The capacitors C1 , C2, C4 and C5 forms Wheatstone bridge such that 6/8 = 3/4 . Therefore, the capacitor C3 gets eliminated.

• Capacitors in series.

Capacitors C2 and C5 are in series . Thus

C25 = 8×4/8+4 = 8/3

For capacitors C1 and C4 that are also in series .

So C14 = 6×3/6+3 = 2

• Capaciotors in parallel.

The capacitors C14 and C25 are in parallel  combination. Therefore, their               equivalent capacitance is

      Ceq1 = 8/3  +  2   =  14/3

Ceq1 and C6 are in series  

Ceq =  (14/3  ×  7) ÷ (14/3 + 7)

      =   (14 × 7)/3  ÷  35 / 3×7

      =  14×7×7 / 35

      = 19.6 mF