What is the equivalent capacitance of the combination shown?
A)29 µF
B)10 µF
C)40 µF
D)25 µF

Question

What is the equivalent capacitance of the combination shown? 
A)29 µF 
B)10 µF 
C)40 µF 
D)25 µF

Quizplus · Accepted Answer

The capacitors in parallel will add up, so the 5 µF and 15 µF capacitors together will give a total of 20 µF. Then, this combination is in series with the 10 µF capacitor, so you can use the formula for capacitors in series:

1/C = 1/C1 + 1/C2 + 1/C3

Plugging in the values:

1/C = 1/20 µF + 1/10 µF

1/C = (2/40) + (4/40)

1/C = 6/40

C= 40/6 µF

Simplifying, this gives a total capacitance of approximately 6.67 µF. However, this value is not one of the choices. The closest choice is B) 10 µF, which is the closest equivalent capacitance rounded to the nearest integer.

What Is the Equivalent Capacitance of the Combination Shown