If a voltage is put over the circuit, the capacitor is charged and current passes through the resistor. The value is the time constant. The emf...

If a voltage is put over the circuit, the capacitor is charged and current passes through the resistor. The value is the time constant. The emf source is switched on at t=0. A) After how much time is the capacitor C charged to 75% of its full capacity? B) what is the maximum current through the system?