1. Mr. Bahaa Abou Harfoush The given diagram represents an electric circuit of an electric motor, lamp, dry cell that provides a constant voltage 12 V, switch and connecting wires. M L AB C D NP First case: the switch K is opened. 1) How are the lamp and the motor connected. (series or parallel)? 2) Determine the voltage across the terminals of the switch, lamp and the motor. Series The voltage across an open switch is equal to the voltage across the generator. (open circuit )

2. M L AB C D NP 3) What is the value of the electric current in the circuit. Mr. Bahaa Abou Harfoush

3. M L AB C D NP Voltage across a closed switch equal to zero (acts as a connecting wire ) Voltage across a connecting wire equal to zero OR ( Law of addition of voltages )

4. Mr. Bahaa Abou Harfoush M L AB C D NP 2) Find the current carried by the lamp and the motor. 100 m.A (Law of uniqueness of current ) V + - (com)

5. Mr. Bahaa Abou Harfoush 4) On the same diagram, show the connection of an ammeter to measure the current in the circuit when it indicates a positive reading. M L AB C D NP V + - (com) A1A1 com