Two capacitors A and B are connected into the circuit shown in the figure below.
Capacitor A has capacitance 
and capacitor B has capacitance 
. The electromotive force (e.m.f.) of the cell is 
. The two-way switch S is initially at position X, and capacitor B is initially uncharged.
State, in terms of and , the expression for the initial charge 
on the plates of capacitor A.
The two-way switch S is now moved to position Y.
State and explain what happens to the charge that was initially on the plates of capacitor A.
Show that the final potential difference (p.d.) 
across capacitor B is given by
Explain your reasoning.
and 
in the circuit is the sum of the charges 
in the capacitors A and B respectively.
