A 21 Ohm resistor and a 9F capacitor are in series with a 6V

A 21 Ohm resistor and a 9F capacitor are in series with a 6V battery. What is the initial current 53 seconds after the circuit is connected? 0.510 Amps 4.3 Amps 1.67 Amps 0.216 Amps

Solution

I0 = V / R = 6 / 21 = 0.285 Volt

after time t:

I = I0 [ e^(-t/RC)]

I = 0.285 [ e^(-53/(9x21))]

= 0.285 [ e^-0.28] = 0.216 Amps