The circuit diagram from the previous page is reproduced at

The circuit diagram from the previous page is reproduced at right for your convenience. Is bulb 2 brighter than, dimmer than, or as bright as bulb 1? Explain. On the circuit diagram above, draw arrows to indicate the direction of the current through each battery and each bulb. Show that your answer is consistent with the student with whom you agreed in part c. Is the current through battery D greater than, less than, or equal to the current through battery C? Explain. If bulb 1 were unscrewed, would the current through battery C increase, decrease, or remain the same? Explain. Consider the following incorrect student statement about circuit IX from the tutorial, shown at right: When I apply Kirchhoff\'s loop rule when the switch is closed the right loop has one battery and two bulbs m series. Thus the potential difference across the battery must equal the sum of potential difference across the bulbs, so each bulb will get half the potential difference of the battery B, and the bulbs will be equally bright* Identify the flaw(s) in the student\'s reasoning.

Solution

e) Apply Kirchoff,s rule to the outer loop. PD across 2 is PD of C+Pd of D. Where as applying the rule to the left loop gives PD across resistor 1 is PD of C. Therefore 2 is brighter than 1.

f) current direction is X to Z and X _Y_Z. (part c is not included in this question)

g) current through battery D is less than through C as current trhrough both the resistors goes through C. current only through resistor 2 goes through D.

h) this removes one pathh for current to flow , current through C decreases.

last question.

flaw is not accounting for presence of battery A. There would not be any current through resistor 12 as both the terminals are at the same potential, connecting two +ve terminals of batteries.