TJC 2025 IP4 Physics WS 13A Practical Electricity Tutorial (Student)

1 Temasek Junior College IP Physics Topic 13: Practical Electricity IP4 Worksheet 13A: Tutorial Name: Class: Date: 1. A 120 W dryer turns 80% of the electrical energy it receives into heat energy. Calculate the amount of heat energy that it generates in 20 s. [1920 J] 2 The light bulbs in the circuit below are identical. The switch S is initially closed. What will happen to the brightness of L1 and L3 if S is opened? L1 L3 A unchanged unchanged B increases Increase C increases Decreases D decreases Increases ( ) 3 The light bulbs in the circuit below have equal resistance. If L4 blows, which of the following correctly describes the change in brightness of the other three bulbs? L1 L2 L3 A increases increases unchanged B decreases decreases unchanged C decreases increases decreases D decreases decreases increases ( ) L1 L2 L3 L4 L1 L3 L2 S

2 4. A circuit is able to light up five lamps as shown in the diagram on the right. All 5 lamps are similar. a. Which lamp, once removed, will cause all the other lamps to go out? [1] b. Which two lamps are equally bright? [1] 5. The diagram shows identical lamps X and Y connected in series with a battery. The lamps light with normal brightness. A third lamp Z is then connected in parallel with lamp X. Explain what happens to the brightness of lamp Y? ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ _____________________________________________________________________ [3] 6. The diagram below shows a battery of e.m.f. 12 V connected in series with a 2.5 Ω resistor and lamps of resistance 1.5 Ω and 2.0 Ω. Calculate (a) the current in the circuit, [1] (b) the power developed in the battery, [1] (c) the voltage across the two lamps, [2]

3 (d) the power developed in each of the lamp, [2] (e) the power loss in the resistor. [1] (f) An additional 3.5 Ω lamp is now connected in parallel to the two current lamps as shown in the diagram below. Describe and explain what happens to (i) the brightness of the two existing lamps, __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________