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.

What is the value of Rth, in figure b) for which circuit b) is equivalent to circuit a)

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

Vc(t)= A. (1-e^s.t )

Considering tx=0,79 ms

Please give the value for  vc( 0,79ms)

(give your answer using 3 decimals)