Phy 202 & 214 Quiz 18 February 20, 2008

Three identical long bulbs are in series as shown. The wires.connecting the bulbs have negligible resistance. In the steady state, 3 x 10¹⁷ electrons leave the battery at location A every second.

1. How many electrons enter the second bulb at location D every second? If there is insufficient information to give a numerical answer, state how it compares with 3x10¹⁷. Justify your answer carefully.

2. Finally, the right-hand bulb (at FG) is replaced by a bulb identical in every way except that its filament has twice as large a cross-sectional area.

Now how many electrons leave the batteries at location A every second? Explain clearly! If you have to make an approximation, state what it is.