In the circuit shown in fig. the switch is kept closed in position 1 for a long time. At time `t = 0` the switch is moved to position 2. Write the dependence of voltage `(V_C)` across the capacitor as a function of time (t). Take `V_(C)` to be positive when plate a is positive.
Given: `R_(1) = 20 Omega, R_(2) = 60 Omega, R_(3) = 400 kOmega, V_(1) = 40 V, V_(2)= 90 V and C = 0.5 mu F`.

Answer

`V_(C)=(90-120 e^(-5t))` volt