Question

What happens when capacitor connected to dc in reduced?

Answer 1

a capacitor allows no current to flow "through" it for DC voltage (i.e. it blocks DC). The voltage across the plates of a capacitor must also change in a continuous manner, so capacitors have the effect of "holding up" a voltage once they are charged to it, until that voltage can be discharged through a resistance

Answer 2

What happens when capacitor connected to dc in reduced?

A capacitor blocks DC as once it gets charged up to the input voltage with the same polarity then no further transfer of electrons can happen accept to replenish the slow discharge due to leakage if any.

Hence the flow of electrons which represents electric current is stopped.