Q. Three capacitors of capacitances $3\mu F,9\mu F$ and $18\mu F$ are connected once in series and another time in parallel. The ratio of equivalent capacitance in the two cases $\left( \frac{C_{s}}{C_{p}} \right)$ will be
A) 1 : 15
B) 15 : 1
C) 1 : 1
D) 1 : 3
Explanation
(a) $\frac{1}{C_{s}} = \frac{1}{3} + \frac{1}{9} + \frac{1}{18} = \frac{1}{2} \Rightarrow C_{s} = 2\mu F$
$C_{p} = 3 + 9 + 18 = 30\mu F \Rightarrow \frac{C_{s}}{C_{p}} = \frac{2}{30} = \frac{1}{15}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.