CBSE Class 12-science Answered

When a capacitor is connected to DC supply, it acts as a short initially (i.e, offers zero resistance) and full current flows through it. Now with time charge starts to accumulate on the plates of capacitor, which develops an opposite voltage difference and reduces the current flow through it.
The current is governed by the equation while charging:
      Q' = Q ( 1 - e^(-t/RC))
      I'= I e^(-t/RC)
where I and Q are initial current and charge respectively. Current through capacitor decreases with time and becomes zero and act as open circuit at t = infinity. Charge on the capacitor which is zero initially begins to build with time. While discharging,  electrons from  the negatively charged capacitor move towards positively charged plate through the circuit and results in a current.Charge on the plates decreases exponentially.