Question

Two capacitors of capacitances `3muF and 5muF` respectively are connected in parallel and this combination is connected in series with a third capacitor of capacitance `2muF`. A potential difference of 100 V is applied across the entire combination. The charge and the potential difference across the third capacitor is
A. `100muC, 40 V`
B. `100muC, 80 V`
C. `160muC, 40 V`
D. `160muC, 80 V`

Answer 1

Correct Answer - D
`C_(P)=C_(1)+C_(2)=3+5=8muF`
`C_(S) = (C_(p)*C_(3))/(C_(p)+C_(3))=(8xx2)/(8+2)=1.6muF`
`Q=C_(S)*V=1.6xx100=160muC`
`V_(3)=(C_(p)/(C_(p)+C_(3)))V=(8/(8+2))100=80V.`