20V
1kΩ
1µF
20V
5kΩ

vc(0-) = 20 V ; ic(0+) = 4 mA
vc(∞) = -20 V ; ic(∞) = 0 mA
τ = 5 ms

vc(t) = -20 + 40e-200t [V] ; t ≥ 0
time for vc to reach 0V: 3.466ms

ic(t) = 20 + 4e-200t [V] ; t ≥ 0
time for ic to reach 0A: never, but 25ms is close