5 11969.03 Question 2 Requirements • 22 Ω resistor × 4 • 15 Ω resistor × 2 • Milliammeter (range 0–200 mA reading to 0.1 mA) • Voltmeter (range 0–20V to 0.01V) • Connecting wires with fitted plug × 5 • Crocodile clips × 2 • 4.5V d.c. supply (batteries or power pack) • Box or similar to conceal power supply • Masking tape • Labels Preparation Use the masking tape to conceal the markings on all the resistors. Label the 22 Ω resistors ‘A’ and the 15 Ω resistors ‘B’. Connect two 22 Ω resistors and a 15 Ω resistor in series. Connect two 22 Ω resistors in parallel with each other and put these in series with a 15 Ω resistor. Conceal the power supply and leave the two end terminals exposed with leads attached. Label the concealed box ‘power supply’. Set the milliammeter to the 200 mA setting and tape the dial in place so that it cannot be moved by the candidate. Before the examination Leave all the equipment on the desk – both resistor networks, the concealed power supply, milliammeter, voltmeter and the remaining three connecting wires and crocodile clips. Action at changeover Disconnect any circuit, returning the apparatus to the original arrangement.