Net capacitance of three identical capacitors in series is `1 muF`. What will be their net capacitance if connected in parallel ?
Find the ratio of energy stored in the two configurations if they are both connected to the same source.

Explanation

It is given that `C_1 = C_2 =C_3 =C` (say)
Then their equivalent capacitance in series `C_s = C/3 =1 mu F`
`rArr C = 3muF`
`:.` Net capacitance in parallel arrangement `C_p = 3C = 3 xx 3 muF = 9 muF`
Let the capacitor combination be connected, in both configurations, to a given source of voltage V. Then
net energy stored in series combination
`u_s = 1/2 C_s.V^2`
and net energy stored in parallel combination
`u_p = 1/2 C_p V^2 rArr u_s/u_p = C_s/C_p = (1 muF)/(9muF) =1/9`.