 AP Free Response Question 2002 B3
Two light bulbs, one rated 30 W at 120 V and another rated 40 W at 120 V, are arranged in two different circuits.

(a) The two bulbs are first connected in parallel to a 120-V source.

 i. Determine the resistance of the bulb rated 30 W and the current in it when it is connected in this circuit.

 ii. Determine the resistance of the bulb rated 40 W and the current in it when it is connected in this circuit.

(b) The bulbs are now connected in series with each other and a 120-V source.

 i. Determine the resistance of the bulb rated 30 W and the current in it when it is connected in this circuit.

 ii. Determine the resistance of the bulb rated 40 W and the current in it when it is connected in this circuit.

(c) Number the bulbs in each situation described, in order of their brightness.

 (1 = brightest, 4 = dimmest) 30 W bulb in the parallel circuit 40 W bulb in the parallel circuit 30 W bulb in the series circuit 40 W bulb in the series circuit

(d) Calculate the total power dissipated by the two bulbs in each of the following cases.

 i. The parallel circuit

 ii. The series circuit