Four resistors, R1 = 100 ohms, R2 = 150 ohms, R3 = 120 ohms, and R4 = 500 ohms, are connected in parallel across a 100V battery. Find (a) the total resistance of the circuit, (b) the total current flowing in the circuit, (c) the current flowing through the 120 ohm (R3) resistor, and (d) the power dissipated by the 500 ohm (R4) resistor.