 2002 B3 Printer Friendly Version
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 Topic Formulas Related Documents