Calculate the circuit's time constant in milliseconds.?

An initially uncharged 3.89*10^6 f capacitor and a 7890 ohm resistor are connected in series to a 1.50V battery that has negligible internal resistance. What is the initial current int he circuit, expressed in milliamperes? Calculate the circuit's time constant in milliseconds. How much time, in milliseconds, must elapse from the closing of the circuit of the current to decrease to 2.93% of its initial value? plz suggest wiil be thankful.