Current in a series circuit Consider the circuit containing three identical light bulbs shown in a top view in the figure. North is indicated in the diagram. Compasses are placed under the wires at locations A and B. - Z B j zero magnitude (a) The magnitude of the deflection of compass A is 10 degrees away from north. Which arrow best indicates the direction in which the compass needle points? ---Select--- (b) What is the magnitude of the deflection of the needle of compass B? degrees What direction does the needle of compass B point? ---Select--- (c) In the steady state 1.4 x 1018 electrons per second enter bulb 1. There are 6.3 x 1028 mobile electrons per cubic meter in tungsten. The cross-sectional area of the tungsten filament in bulb 1 is 1 x 10-8 m2. The electron mobility in hot tungsten is 1.2 x 10-4 (m/s)/(N/C). Calculate the magnitude of the electric field inside the tungsten filament in bulb 3. V/m