PhysicsLAB 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





CB-ETS
Copyright © 1970-2022
All rights reserved.
Used with permission
Mainland High School
Daytona Beach, FL 32114