If a 0.1 $\mu F$ , 0.1 $\mu \mathrm { F }$ and 0.05 $\mu \mathrm { F }$ capacitor are connected in series across a 75 V source, the voltage drop across the smallest capacitor equals_____
A) 50 V
B) 100 V
C) 37.5 V
D) 18.8 V

Question

If a  0.1 $\mu F$ , 0.1 $\mu \mathrm { F }$ and  0.05 $\mu \mathrm { F }$ capacitor are connected in series across a  75 V source, the voltage drop across the smallest capacitor equals_____
A)  50  V
B)  100  V
C)  37.5 V
D)  18.8  V

Quizplus · Accepted Answer

Capacitors in series add up like resistors in parallel. So the equivalent capacitance is:$$C_{eq} = \frac{1}{C_1} + \frac{1}{C_2} + \frac{1}{C_3} = \frac{1}{0.1 \mu F} + \frac{1}{0.1 \mu F} + \frac{1}{0.05 \mu F} = 0.02 \mu F$$The voltage across each capacitor is:$$V_1 = V_2 = V_3 = V_{eq} = 75 V 	imes \frac{C_{eq}}{C_1} = 75 V 	imes \frac{0.02 \mu F}{0.05 \mu F} = 37.5 V$$

If a 01 μF\mu FμF , 01 μF\mu \mathrm { F }μF

If a 01 $\mu F$ , 01 $\mu \mathrm { F }$