Question

A parallel plate capacitor(C1) having charge Q is connected ,to a uncharged capacitor (C2) in parallel.What would be the charge accumulated on the capacitor C2 ?

Answer 1

ctotal=c1+c2
ctotal=q1/v1+q2c2

Answer 2

When a charged and an uncharged capacitor  is connected in series, the charges re-distribute themselves in the direct connection to their capacitance, holding the whole charge of the circuit fixed.

So, charge across C2 is Q/2.

Mathematically,

Let the charge, capacitance and voltage of the two capacitors be, Q1, C1, V1 and Q2, C2, V2 respectively.

Because they are attached in series,

V=V1+V2 = Q1/C1 = Q2/C2

We know, C1 = C2 = C

Hence, V= (Q1+ Q2)/C