Question

Two capacitors are connected in series and the combination is charged to 120V. There's 90.0V across one capacitor, whose capacitance is 0.28?F What is the capacitance of the second capactior?

Answer 1

0.84μF

Step-by-step explanation:

Charge is same through both the capacitors since they are in series. Total voltage is the sum of the voltages of the individual capacitors.. So voltage across the 2nd capacitor is 120- 90 =30 V.

Charge across first capacitor is Q = C₁V₁ = 90 x0.28 = 25.2μC

Therefore capacitance of 2nd capacitor =

C₂ = Q÷V₂ = 25.2÷30 = 0.84 μF