EXCELLENCE INTERNATIONAL SCHOOL First Term, Work sheet (1) Grade (9) Academic Year 2014-2015 Subject: quantities Topics:- Static electricity - Eelectrical NAME: DATE: MULTIPLE CHOICE QUESTIONS: 1 - A circuit is set up with a gap between two terminals X and Y. The four strips of material shown in the diagram are connected in turn across the gap. Which strip completes the circuit so that the lamp lights? 2- Which diagram correctly shows the electric field between two charged spheres? 1
3- On a stormy day, a large, positively-charged cloud is above a tree. An electrical charge is induced on the tree as charged particles flow through it. What is the charge induced on the tree and how do the charged particles move? 4- In the circuit shown, the reading on ammeter 1 is 2 A. What is the reading on ammeter 2? a- 0 A b- 1 A c- 2 A d- 4 A 5-A student wishes to measure the electromotive force (e.m.f.) of a battery and the potential difference (p.d.) across a resistor. She has the resistor, the battery and some connecting wires. What else does she need? a- a voltmeter only b- an ammeter only c- an ammeter and a voltmeter 2
d- a force meter (newton meter) and a voltmeter 6- In the circuit below, X and Y are identical 6 V lamps. What happens when the switch is closed? A X lights more brightly than Y. B Y lights more brightly than X. C X and Y light with equal brightness. D Neither X nor Y light. 7- During a physics lab, a plastic strip was rubbed with cotton and became positively charged. The correct explanation for why the plastic strip becomes positively charged is that... a. the plastic strip acquired extra protons from the cotton. b. the plastic strip acquired extra protons during the charging process. c. protons were created as the result of the charging process. d. the plastic strip lost electrons to the cotton during the charging process. 8- The diagram shows a circuit with three ammeters, X, Y and Z. Which set of readings is possible? 9-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. 3
10-The circuit shows a current I in a resistor of resistance R. Which line gives possible values of I and of R? 11- Which of these is an electric current? A a beam of atoms B a beam of electrons C a beam of molecules D a beam of neutrons 12- The diagram shows a battery connected to three identical resistors. Four ammeters A, B, C and D are connected in the circuit. Which ammeter shows the smallest reading? 4
ANSWER THE FOLLOWING QUESTIONS: 1- This question refers to quantities and data shown on the circuit diagram of Fig. 9.1. (a) State the relationship between (i) the currents I1, I2 and I3,... (ii) the currents I1 and I4.... (b) The ammeter reads 0.80 A. Assume it has zero resistance. Calculate (i) the potential difference between X and Y, (ii) the current I3, p.d. =... (iii) the resistance of R. current =... resistance =... 2- (a) In a room in a house there are four electric lamps in parallel with each other, controlled by a single switch. With all the lamps working, one of the lamp filaments suddenly breaks. What, if anything happens to the remaining lamps? Explain your answer.... 5
(b) Fig. 10.1 shows the circuit diagram for the lamp in another room. X and Y are 2-way switches. (i) Complete the table, by indicating whether the lamp is on or off for each of the switch positions. (ii) Explain why this arrangement of switches is useful....... 0625/03/O/N/07 3-. 8.1 shows a low-voltage lighting circuit. (a) On Fig. 8.1, indicate with a dot and the letter S, a point in the circuit where a switch could be placed that would turn off lamps Y and Z at the same time but would leave lamp X still lit. (b) (i) In the space below, draw the circuit symbol for a component that would vary the brightness of lamp X. (ii) On Fig. 8.1, mark with a dot and the letter R where this component should be placed. (d) The current in lamp Z is 3.0 A. Calculate the resistance of this lamp. resistance =... 6
(e) The lamp Y is removed. (i) Why do lamps X and Z still work normally?...... (ii) The current in lamp X is 1.0 A. Calculate the current supplied by the battery with lamp Y removed. current =... **************************************** 4-The IGCSE class is investigating the resistance of a lamp filament. The circuit is shown in Fig. 4.1. a-a student connects the sliding contact S to point X in the circuit. She measures the potential difference V across the lamp and the current I in the circuit. The meters are shown in Fig. 4.2. (i) Write down the readings shown on the meters in Fig. 4.2. V =... I =... 7
(ii) Calculate the resistance R of the lamp filament using the equation R = VI. R =... (b) The student repeats the steps in (a) with the sliding contact S at point Y and then at point Z. Comment on the effect, if any, on the brightness of the lamp that you would expect to see when the sliding contact is moved from X to Y to Z.... (c) The student moves the sliding contact S back to point X. Suggest one practical reason why the new meter readings might be slightly different from those shown in Fig. 4.2.... (d) Another student carries out the experiment using a different lamp. He takes readings using various lengths of resistance wire in the circuit. He plots a graph of V / V against I/A. Fig. 4.3 is a sketch of the graph. State whether the graph shows that the resistance increases, decreases or remains constant as the current increases. Justify your conclusion by reference to the graph. The resistance.... justification... 8
5- Two conducting spheres are rubbed and become charged, as shown in Fig. 5.1. (a) The spheres are uncharged before they are rubbed. Explain, in terms of the movement of electrons, how they become charged............. (b) On Fig. 5.1, draw the electric field pattern between the spheres. Show the direction of the field lines. (c) A metal wire is used to connect the two spheres together. In a time of 2.0 10 3 s, charge of 1.8 10 13 C passes through the wire. Calculate the current in the wire. current =... 9