A 5.0 uF capacitor is charged to a p.d of 10v. It is then removed from the supply and connected in parallel with an uncharged 20 uF capacitor. Calculate the charge on each capacitor after connection

Question

A 5.0 uF capacitor is charged to a p.d of 10v. It is then removed from the supply and connected in parallel with an uncharged 20 uF capacitor. Calculate the charge on each capacitor after connection
(My working so far,
   5×10^-6×10=5×10^-5C )I am stumped on what to do any further

bobpursley · Answer

charge stored: 5E-5 (CV)
now, when connected, the two capacitors have equal voltages..

V=Q1/C1 =Q2/C2
but Q1+Q2= original charge , or
Q1+Q2=(5E-6 *10)
q2=5E-5-Q1

V=Q1/C1 =Q2/C2
Q1=C1/C2 * (5E-5-Q1) and C1/C2=1/4
which leads to
5/4 Q1=1/4*(5E-5)
Q1=.... then solve for Q2