what is the voltage(v) lost at the 75 ohm resistor?

1. What is the total resistance of the circuit?

Total resistance = 50 ohms + 1/(1/45 ohms + 1/90 ohms) = 50 ohms + 30 ohms = 80 ohms.

Total resistance = 80 ohms.

2. What is the total current leaving the battery?

I = V/R = 8V/80 ohms = 0.1 Amps.

3. What is the current through the 45 ohm resistor? Use the total resistance of the parallel set, ie. 30 ohms.

V = IR = (0.1 amps) x (30 ohms) = 3 volts

I = V/R = 3 V / 45 ohms = 1/15 amp = 0.067 Amps.

4. A 1200 Watt hair dryer is plugged into a 120 volt circuit. What is the current drawn by the hair dryer?

P = IV

I = P/V = 1200 W / 120 V = 10 Amps.

For questions 5 - 8, please refer to the circuit below.