2. A student sets up the circuit shown. The switch is open (off). Which lamps are on and which lamps are off?

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Curtis Byrd
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1. A polythene rod repels an inflated balloon hanging from a nylon thread. What charges must the rod and the balloon carry? A The rod and the balloon carry opposite charges.

1 1. A polythene rod repels an inflated balloon hanging from a nylon thread. What charges must the rod and the balloon carry? A The rod and the balloon carry opposite charges. B The rod and the balloon carry like charges. C The rod is charged but the balloon is not. D The balloon is charged but the rod is not. 2. A student sets up the circuit shown. The switch is open (off). Which lamps are on and which lamps are off? 3. The diagram shows an electric circuit containing three meters, X, Y and Z, all connected correctly. What are meters X, Y and Z? 1

2 4. A student uses a length of wire as a resistor. He discovers that the resistance of the wire is too small. To be certain of making a resistor of higher value, he should use a piece of wire that is A longer and thicker. B longer and thinner. C shorter and thicker. D shorter and thinner. 5. The diagram shows a battery connected to two identical resistors. Three ammeters M1, M2 and M3 are connected in the circuit. Meter M1 reads 1.0 A. What are the readings on M2 and on M3? 6. Fig. 8.1 shows two electrical circuits. 2

3 (a) Put ticks in the table below to describe the connections of the two resistors P and Q. (B) In circuit 1, the ammeter reads 1.2 A when the switch is closed. Calculate the reading of the voltmeter in this circuit. voltmeter reading =... [2] (C) The two switches in circuit 2 are closed. Calculate the combined resistance of the two resistors in this circuit. combined resistance =... [2] (D) When the switches are closed in circuit 2, ammeter 1 reads 5 A and ammeter 2 reads 2 A. Calculate (i) the current in resistor P, current =... [1] 7. The IGCSE class is investigating the potential difference across lamps and the currents in the lamps. Fig. 3.1 shows the circuit that is being used. 3

4 (a) A student uses the ammeter to record the current I in the wire connecting the power source to the rest of the circuit. He then moves the ammeter to new positions in the circuit and measures the current in each lamp in turn. The positions of the pointer on the ammeter scale are shown below. Write down the ammeter readings I, I1, I2 and I3. [3] (b) Theory suggests that I = I1 + I2 + I3. State whether or not your readings support this theory. Give a reason for your answer. Statement... Reason [1] (C) The student uses a voltmeter to measure the potential difference V across the lamps. His reading is V = 1.6 V. (i) Calculate the resistance R of the lamps arranged in parallel, using the equation R = V / I, where I is the value of the current in (a)(i). R =... (ii) On Fig. 3.1, add the symbol for the voltmeter connected to measure the potential difference across the lamps. [3] 4

5 8. The IGCSE class is comparing the combined resistance of lamps arranged either in series or in parallel. The circuit shown in Fig. 3.1 is used. A student measures and records the current I in the circuit and the p.d. V across the two lamps. Fig. 3.2 shows the readings on the two meters. (a) (i) Write the voltage and current readings in Table 3.1, below. (ii) Complete the column headings in Table 3.1. [3] (b) The student then sets up the circuit shown in Fig. 3.3 and records the readings. These readings have already been entered in Table 3.1. For each set of readings in the table, calculate the combined resistance R of the two lamps using the equation R = V / I. Record the values of R in Table 3.1. [2] (c) Using the values of resistance you have obtained, calculate the ratio y of the resistances using the equation Y =. 5

ELECTRICITY & MAGNETISM - EXAMINATION QUESTIONS (4)

ELECTRICITY & MAGNETISM - EXAMINATION QUESTIONS (4) 1. Which two electrical quantities are measured in volts? A current and e.m.f. B current and resistance C e.m.f. and potential difference D potential