Consider the circuit represented in a) where C1=9,31 nF, R1=138,8 KΩ and I1=2,0 mA .

Consider circuit b) and the values for Rth and Vth previously obtained.

It is known that the overall response of the voltage in the capacitor will be given by 

Vc(t)= A. (1-e^s.t )

Please indicate the value for t, at which the transient response is nulled. 

(Please give the time in mili seconds and give your answer using 3 decimals)