1. A 12 V battery is connected in a circuit. An ammeter reads 2 A. What resistance is connected in the circuit? What power is dissipated in the circuit? What electrical energy is used after 4 sec?
2. Repeat number one using a 120 V battery, an ammeter reading 1.5 A, and a time of 3 min.
3. An 8 W resistor, a switch, and a 12 V battery are connected in a circuit. Draw the circuit diagram. Calculate the current.
4. A 60 W bulb is connected to 120 V. What is its resistance?
5. A 30 W bulb is connected across 120 V. What is its resistance? What electrical work is done in 10 sec?

1. A circuit consists of a 5 W and a 10 W resistor in series across a 45 V battery. A voltmeter is connected across each resistor. An ammeter measures total current. A switch is also included. Calculate the total current and the voltage drops across each resistor. Draw the circuit.
2. Three resistors, a 5 W, a 10 W, and a 15 W, are connected in series. Each has a voltmeter. A switch and an ammeter are included, as well as a 30 V battery. What does the ammeter read? What is the voltmeter reading across the 10 W resistor? Draw the circuit.
3. What is the total resistance and the voltage drop, V? What is the power dissipated in the 6 W resistor? What is the electrical energy used by the 6 W resistor in 20 seconds? What is the magnitude of R?
4. What is the total resistance and the voltage drop, V, across the 6 W resistor. What is the power dissipated in the 4 W resistor? What is the electrical energy used by the 4 W resistor in 10 sec? What is the magnitude of R?
5. What is the magnitude of R?

1. A 12 W, a 20 W, and a 24 W resistor are connected in parallel across 120 V. A voltmeter is connected across each resistor. Each parallel branch has its own ammeter following the resistor. A switch is located in the main circuit. An ammeter measures total current. Draw the circuit. Determine the total current. Determine the effective resistance. Find the current through the 20 W resistor.
2. Four 18 W lamps are connected in parallel across 6 V. What is the current in each? What is the resistance of each? What is the effective resistance?
3. A 60 W. a 20 W, and a 10 W resistor are connected on a house line. Will a 15 amp fuse blow?
4. A 6 W resistor is connected in parallel with an unknown resistance, R and a 12 V battery. The ammeter reads 3 A. What is the magnitude of R?

### Complex Circuits Sample Problems

1. Calculate the total current. Calculate the voltage drop across the 36 W resistor. Calculate the voltage drop across the 16 W resistor. Calculate the current through the 48 W resistor.

2. Calculate the total current. Calculate the voltage drop across the 8 W resistor. Calculate the voltage drop across the 12 W resistor. Calculate the current passing through the 12 W resistor.

3. Calculate the total current. Calculate the voltage drop across the 8 W resistor. Calculate the voltage drop across the 12 W resistor. Calculate the current passing through the 12 W resistor.

Electric Circuits Notes