TP 21.56

Given: C₁ = 7.50 mF = 7.50 x 10^-6 F

C₂ = 15.0 mF = 15.0 x 10^-6 F

DV = 12.0 V

(a) Find: C₁₂ - ?

C₁₂ = C₁ + C₂ = 15.0 mF + 7.50 mF = 22.5 mF

(b) Since Q = C DV, the capacitor 2 which has larger capacitance will store more charge (note that the capacitors are in parallel to each other, the potential difference across each is 12.0 V).

(c) Q₁ = C₁ DV = (7.50 mF) (12.0 V) = 90.0 mC

Q₂ = C₂ DV = (15.0 mF) (12.0 V) = 180 mC