Beibei weather

(Investigation scope: circuit, current, voltage and resistance)

Name _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

First, multiple-choice questions (this question contains 50 small questions)

1.(04 Chenzhou, Hunan) The instrument that can detect whether an object is charged is ().

A. watt-hour meter B. voltmeter C. ammeter D. electroscope

2.(05 Hebei Province) Brush your hair with a plastic comb a few times, the comb will be charged, and the comb will be negatively charged after inspection. The following statement is correct ().

A. there are some electrons on the comb. The comb lost some electrons.

C. the comb dropped some nuclei. Friction produces electric charge.

3.(04 Beibei, Chongqing) When a rubber rod with fur touches the metal ball at the top of the electroscope, the metal foil at the bottom of the electroscope will open at a certain angle. The correct explanation for this phenomenon is ().

A. the protons on the rubber rod are transferred to the metal foil.

B. Both metal foils are positively charged, which repel each other and open.

C. the electrons on the electroscope are transferred to the rubber rod.

D, both metal foils are negatively charged, which repel each other and open.

4.(04 Gansu) When the physics teacher was teaching the lesson of "friction and electrification", he asked the students to rub their hair with a plastic ruler several times, and then tried to see if they could attract scraps of paper. As a result, the plastic ruler will attract scraps of paper. If the friction between rubber rod and fur is taken as an analogy, this phenomenon shows ().

A. When rubbing, positive and negative charges are transferred at the same time, the hair is negatively charged, and the plastic ruler is positively charged.

B. When rubbing, the positive and negative charges are transferred at the same time, the hair is positively charged and the plastic ruler is negatively charged.

C. When rubbing, only positive charges are transferred, so that the plastic ruler is positively charged.

D. When rubbing, the electrons in the hair are transferred to the plastic ruler, which makes the plastic ruler negatively charged.

5.(04 Xinjiang Construction Corps) Among the following phenomena, the one that does not belong to friction electrification is ()

A. a pen rubbed with hair will attract scraps of paper.

B.magnets can attract steel needles.

C. When brushing woolen clothes with a dry brush, a lot of fine dirt will be adsorbed on the brush.

D. When you take off your sweater in dry weather, you can hear a slight "click" sound and even see sparks at night.

6.(05) There are two through-grass balls suspended by silk thread, one charged and the other uncharged. When two balls are close, the impossible phenomenon is ().

A. these two balls repel each other. Two balls attract each other.

C. charged close to uncharged

7.(04 Dalian) Among the following groups of substances, the group that is usually a conductor is ()

A. Human body, salt water and rubber B. Human body, soil and oil

C. Metal, clay and ceramics D. Salt water, human body and clay

8.(04 Luquan Experimental Area, Hebei Province) The following groups of substances are normally insulators ()

A. metal, salt water, rubber B. plastic rod, limewater, pencil lead.

C. ceramics, oil and dry sticks D. copper sulfate solution, mercury and sodium hydroxide solution.

9.(05 Nanning) In general, the following substances belong to the insulator ().

A. Ceramics and petroleum B. Tap water and glass

C. plastic shoes, the earth D. human body, air

10.(05 Suzhou) Among the following school supplies, () belongs to the conductor in general.

A. plastic scale B. physics textbook C. drawing rubber D. metal small blade

1 1.(05 Fuzhou Curriculum Reform Area) As shown in the figure, several materials used to make pencils are marked. Usually, belongs to the insulator is ().

A. Wood and rubber B. Graphite and metal C. Wood and metal D. Graphite and rubber

12.(04 Henan) As shown in the figure, it is a structural sectional view of a button switch. In the figure, C is the button, D is the shell, and A and B are connected to the circuit with red terminals, where ().

A, A, B and C are conductors and D is insulator.

B.a, b and d are conductors and c is an insulator.

C.a and b are conductors, and c and d are insulators.

D, C and D are conductors, and A and B are insulators.

13.(04 Nanjing) Among the objects shown in the figure, the group whose materials are all insulators is ().

14.(05 Wuhan) Xiaogang took apart the incandescent bulb and lamp holder commonly used in household circuits, as shown in the figure, so the following parts on the bulb and lamp holder belong to insulators ().

A. back cover and screws of lamp holder

B. glass bubbles and tin blocks

C. Spiral metal plate

D. lamp holder and back cover of glass bulb

15.(05 Chengdu, Sichuan (non-curriculum reform)) Regarding conductors and insulators, the following statement is true ().

A graphite is a conductor and rubber is an insulator. B. The human body is a conductor and the earth is an insulator.

C all metals are conductors and all nonmetals are insulators.

D. solids are conductors and liquids are insulators.

16.(05 Shenyang (non-curriculum reform area)) The following is reasonable about the classification of teaching materials ()

A. Oil, dry wood and ceramics are insulators. Pencil lead, rubber and iron are all conductors.

Iron, ice and glass are conductors. Beeswax, salt and mercury are amorphous.

17.(04 Wuhan) Of the following statements about conductors and insulators, the correct one is ().

A. A conductor can conduct electricity because there is a lot of charge in it.

B. Insulators are not easy to conduct electricity because there is no charge in them.

C. Conductors can conduct electricity under any circumstances, and insulators will not conduct electricity under any circumstances.

Some insulators will become conductors under certain conditions.

18.(04 Taizhou) The following statement is true ()

The electroscope can not only check whether the object is charged, but also measure the amount of charge of the object.

B. the direction of current is the direction of directional movement of electrons.

C. Insulators are not easy to conduct electricity because there are no electrons in them.

D. lightning is a discharge phenomenon that occurs in nature.

19.(03 Harbin) About the knowledge of circuits, the following statement is incorrect ().

A. In order to make two lights turn on and off at the same time, two lights must be connected in series.

The direction of current in metal is opposite to the direction of directional motion of free electrons.

C in the circuit, the power supply is a device that converts other forms of energy into electrical energy.

D. The general circuit consists of power supply, electrical appliances, switches and wires.

20. Of the four circuits shown in the (04 Guangdong) diagram, the one corresponding to the physical diagram on the right is ().

2 1.(04 Taiyuan) In the circuit shown in the figure, the correct circuit for the switch S to control the lamp and the bell at the same time is ().

22.(04 Chaoyang District, Beijing) In each circuit shown below, two light bulbs are connected in parallel ().

23.(04 Dalian, Liaoning) Every holiday night, many tall buildings are decorated with thousands of light bulbs. The lighted bulb reflects the outline of the building and looks beautiful and spectacular. These light bulbs are ().

A. parallel B. series C. it may be series or parallel D. it is impossible to judge.

24.(05 Laibin City, Qinzhou City, Guigang City) In the circuit as shown in the figure, when S 1 and S2 are closed, then ().

A.l 1, L2 series connection

B.L 1, L2 in parallel

C. lamp L 1 short circuit.

D.L2 lamp short circuit

25.(05 Guilin Curriculum Reform Area) As shown in the circuit, if the power supply voltage is appropriate, the electric bell and the electric lamp can have current at the same time. The correct one in the following practices is ().

A. disconnect Sl and close S2 and S3; Disconnect S3 and close S 1 and S2.

C. close Sl and disconnect S2 and S3; D close S2 and disconnect S 1 and S3.

26.(04 Guangzhou) In the illustrated circuit, if two lamps L 1 and L2 are to form a parallel circuit, the opening and closing conditions of the switch are ().

A.S 1, S2 is open, S3 is closed.

B.S 1, S2 closed, S3 opened.

C.S 1, S2 and S3 are closed.

D.S 1 open, S2 and S3 closed.

27.(05 Tai 'an City) The following picture shows four control circuits of stair lighting designed by Xiao Ming, in which S 1 and S2 are upstairs and downstairs switches respectively (both are single-pole double-throw switches). You need to toggle any switch to change the original state of lighting or extinguishing. In practical application, the best scheme is ()

28.(05 Zigong City) The formula I=Qt is correctly understood as ().

A. the longer the conductor is energized, the smaller the current.

B the more charge passes through any cross section of the conductor in 1s, the greater the current in the conductor.

C. The greater the amount of charge passing through the cross section of the conductor, the greater the current in the conductor.

The larger the cross section of the conductor, the greater the current in the conductor.

29.(04) Anhui common household appliances, about their normal working current, the following statement is reasonable ().

A. the electric fan is about 2A B, the refrigerator is about 1A C, the TV is about 2A D, and the desk lamp is about 1A.

30.(05 Yancheng) The circuit is shown in the figure. After closing the switch, compare the currents in A, B, C and D, and the incorrect one is ().

A.Ia=Id B.Ia>Id

C.Ia>Ib D.Id>Ic

3 1.(05 Wuhan) As shown in Figure (a), when the switch S is closed, the readings of two ammeters are read from Figures (b) and (c) respectively, and the current in the lamp L 1 is ().

a . 0.8a b . 0. 16A c . 0.52 a d . 1.28 a

32.(04 Guiyang Experimental Zone) Which of the following statements is the characteristic of parallel circuits? ( )

A. the currents in all parts of the circuit are equal.

B any break in the circuit will lead to an open circuit.

C. the voltage on each branch is equal.

D the sum of the voltages of all parts on the circuit is equal to the total voltage.

33.(05 Guilin Curriculum Reform Area) In the circuit diagram shown in the figure, it is () that can correctly measure the voltage across the lamp Ll with a voltmeter.

34.(05 Suzhou) As shown in the figure, AB and BC are two conductors with the same material, the same length and different cross-sectional areas. Connect them in series before connecting them to the circuit. Comparing the voltage across the two conductors with the current through them, there is ().

A.，b，

C.，d，

35.(05, Chengdu, Sichuan (non-curriculum reform)) In a circuit composed of power supply, switch, wire and two small bulbs, when measured with a voltmeter, it was found that the voltages at both ends of the two bulbs were equal, and the brightness of the two bulbs was different. Connection of two small bulbs ()

A. it must be parallel. B.it must be a series.

C. it can be connected in series or in parallel. D. it is impossible to judge.

36.(04 Nanchang, Jiangxi) In the circuit shown in Figure A, when the switch is closed, the pointers of the two voltmeters deflect as shown in Figure B, so the voltages across the resistors R 1 and R2 are () respectively.

4.8V， 1.2V

C. 1.2V，6V d . 1.2V，4.8V。

37.(05 Suqian City) Regarding resistance, the following statement is correct ()

Insulators don't conduct electricity easily because they have no resistance.

B. the resistance of conductors and insulators is only related to materials.

After the copper wire is stretched evenly, its resistance becomes larger.

The resistance of copper wire must be less than that of aluminum wire.

38.(05 Hechi, Guangxi) To change the size of conductor resistance, the following method is invalid ().

A. changing the voltage across the conductor B. changing the material of the conductor

C, changing the cross-sectional area d and the length of the conductor.

39.(04 Hebei Comprehensive) Give you two nickel-chromium alloy wires with the same length but different cross-sectional areas, a power supply, an ammeter, a sliding rheostat, a switch and several wires. The topics that need to be studied now are: ① the relationship between the resistance of conductor and its cross-sectional area; (2) The relationship between the resistance of a conductor and its length; ③ The relationship between the resistance of a conductor and its material. The research topic that the above experimental equipment can complete is ()

A.only 1 b.only 2 c.1 and 2 d.1, 2 and 3.

40.(05 Wuhu City) When conducting experimental research on the influence of conductor material, length and cross-sectional area on resistance, the available conductor specifications are as follows:

What do you think is the most reasonable group for the conductor to choose ()

A.③④⑤⑥b .②③⑥⑦c .①⑤⑥⑦d .⑤⑥⑧①

4 1.(04 Lishui Nature, Zhejiang Province) The following figure is a schematic diagram of the access circuit of the sliding rheostat, in which the resistance of the access circuit cannot be changed by moving the slider is ().

42.(05) The sliding rheostat shown in the figure of the 11th city of Liaoning Province (non-curriculum reform area) should be connected with a small light bulb in series in the circuit. When the slider P slides to the B end, the small light bulb becomes dim, and the two terminals of the sliding rheostat connected in the circuit should be ().

A.CD B.AD C.CB D.AB

43.(04 Chenzhou, Hunan) As shown in the figure, when the switch S is closed and the slider P of the sliding rheostat moves to the right, the reading of the ammeter will be ().

A. Larger B. Smaller C. Constant D. Uncertain

44.(05 Nanning) In the circuit shown in the figure, the small light bulbs L 1 and L2 are marked with the words "3V 0.25A", and the power supply consists of three 1.5V dry cells. The following statement is incorrect ().

After A.S is turned off, L 1 and L2 are connected in parallel, and both of them can emit light.

When B.S. is turned off, the circuit will be short-circuited.

C. if L 1 and L2 are connected in series, conductor b can be removed.

D. If the M line is switched from the B end to the A end, both lamps can emit light normally.

45.(04 Lianyungang) A classmate accidentally switched the positions of the voltmeter and ammeter when doing electrical experiments, as shown in the figure. If the switch is closed, the consequence is ().

A. two watches will be burned out

B.two watches won't burn out.

C. the voltmeter will not burn out, but there is no indication.

The voltmeter will not burn out, but the ammeter may burn out.

46.(04 Chenzhou, Hunan) As shown in the figure, the power supply, wires and switches are in good contact. When the switch S is closed, the two lights do not light up. At this time, the voltage between A and B is measured to be U, the voltage between A and C is also U, and the voltage between B and C is zero. Therefore, it can be judged that the fault of the circuit may be _ _ _ _ _ _ _ _ _ _ _.

47.(04 Suqian, Jiangsu) The picture shows the circuit diagram of a classmate doing an experiment. When the switch S is closed, it is found that the light bulbs L 1 and L2 are not lit, the current is zero, and the voltage is equal to the power supply voltage, so the fault in this circuit is ().

A. open circuit between positive pole of power supply and a. Open circuit between b.a., L 1 and B.

Open circuit between breaker, L2 and DC. Open circuit between DC and negative pole of power supply.

48.(04 Heilongjiang) When Xiao Ming was doing an electrical experiment, he connected a circuit according to the picture on the right, and the power supply voltage remained unchanged. When the switch is turned on, all lights L 1L2 are on. After a while, one of the lights suddenly went out, but the readings of the ammeter and voltmeter did not change. The reason for this phenomenon is ()

A. lamp L 1 short circuit B. lamp L2 short circuit C. lamp L 1 open circuit D. lamp L2 open circuit.

49.(04 T) In the circuit shown in the figure, the power supply voltage is constant, and the resistance R 1 =R2 ... When the switch is closed, if two current indicators are found to be equal and both are within the normal range, the fault is ().

A.R 1 short circuit B.r 1 open circuit C.R2 short circuit D.R2 open circuit.

50.(05 Nanjing) As shown in the circuit, after the switch is closed, two identical lamps can emit light. After a while, the two lights suddenly went out at the same time, and the readings of voltmeter and ammeter became zero. If there is only one fault in the circuit, the fault may be ().

A. the light L 1 is turned on. L2' s light is on.

C. lamp L 1 D is short-circuited. Lamp L2 short circuit

Fill in the blanks (this question contains 19 small questions)

5 1. (Dalian, Liaoning 04) When cleaning the room, Xiaogang wiped the mirror with dry silk and found that the brushed mirror was easy to stick with tiny fluff. This is because the mirror he wiped was charged by _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

52.(04 Harbin) Dust often sticks to the TV screen. This is because when the TV is working, it has the nature of _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

53.(04 Tianjin) When the glass rod rubs against the silk, the glass rod loses the _ _ _ _ _ _ charge of the electronic band, and the silk gains the same _ _ _ _ _ charge of the electronic band.

54.(04) There are three charged balls in Qinghai. A.B.C If ball A is positively charged, ball C attracts ball B, and ball B repels ball A, then ball B is charged with _ _ _ _ _ _ _ _ _; Ball C has _ _ _ _ _ _ _. (Fill in "positive" or "negative").

55.(05 Hebei Curriculum Reform Area) The picture shows pliers commonly used by electricians, whose design and use have applied a lot of physical knowledge. Among them, the pliers handle is covered with a layer of rubber, which is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

56.(04 Huai 'an, Jiangsu Province) Electric lamps are common lighting appliances in household circuits. The shell and wick of the light bulb are made of glass, which makes use of the _ _ _ _ _ _ performance of glass. If the glass wick is connected to the circuit shown on the right, when the glass wick rises to a certain temperature, the pointer of the small-range ammeter will _ _ _ _ _ (fill in "Yes").

57.(05 Shantou City (Curriculum Reform Area)) Connection mode of TV, refrigerator, electric light and other electrical appliances in household circuits; The switch is connected with the controlled electrical appliance; In order to prevent electric shock accidents caused by electric leakage, the shell of the household washing machine must be _ _ _ _ _.

58.(04 Beijing) Physically, the direction of directional motion of _ _ _ _ _ charge is defined as the direction of current. If the amount of charge passing through the filament section within 30s is 15C, the current in the filament is _ _ _ _ _ _ _ _ a.

59.(05 Guilin Curriculum Reform Area) The working current of fluorescent lamp is about 0. 15A, which is _ _ _ _ _ _ _ ma. Before using the ammeter, check whether the pointer points to the _ _ _ _ _ _ position.

60.(04 Shenyang) When measuring current with ammeter, some students connected the circuit with the range of 0-0.6A, but the reading was 2.4A in the range of 0-3A, so the actual measured current should be _ _ _ A. 。

6 1. (Quanzhou, 05) As shown in the figure, A and B can form a parallel circuit of two small bulbs. (Fill in "light bulb" or "ammeter")

62.(05 Guigang City, Qinzhou City, Laibin City) In the experiment of "measuring current with ammeter", a classmate connected the circuit as shown in Figure (a). When the switch is closed, both lamps emit light, and the positions pointed by the hands of the two ammeters are as shown in Figure (b), then the current through lamp L2 is ___A, and the power through lamp L 1 within 10s is _ _ _ C.

63.(05 Suzhou) The power supply voltage of domestic circuits in China is _ _ _ _ _ V; Voltage not higher than _ _ _ _ _ V is safe for human body.

64.(05 Shanghai) The voltage of ordinary dry batteries is _ _ _ _ _ _ volts. In Figure L, terminal A is the _ _ _ _ _ _ _ pole of the dry cell (choose "positive pole" or "negative pole").

65. The (04 Quanzhou, Fujian) language repeater needs a 6V power supply when it works, which can be composed of _ _ _ _ _ _ _ _ _ _ _ _ _.

66.(04 Meizhou) In the circuit shown in the figure, connect appropriate ammeters on coils A, B and C, so that lights L 1 and L2 can be connected in parallel and emit light, then A should be a _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _; B is a _ _ _ _ _ table; C is _ _ _ _ _ _ _ table.

67.(05 Nanning) The circuit shown in Figure (a) is used for experiments. Turn on the switch S, and find that the light is off, the ammeter has no indication, and the voltmeter has an indication. The fault may be; After troubleshooting, close the switch S to get the current representation as shown in Figure (b), with a reading of A. ..

68.(04 Shanxi) Fold a thin iron wire with uniform thickness in half. If half of the resistance is cut off, the resistance of the remaining part is _ _ _ _ _ _ (fill in "bigger", "smaller" or unchanged).

69.(04 Henan) Rotating resistance box is a kind of rheostat that we often use in the laboratory. The indicator of the resistance box shown on the right is _ _ _ _ _ _ _ _ Ω.

Third, multiple-choice questions (this question contains 2 small questions)

70.(05 Guangdong Province) Knife switch is as shown in the figure ()

A. The porcelain handle is an insulator B. The rubber is an insulator.

C. The moving contact is an insulator and the static contact is a conductor.

7 1.(05 Tianjin) In the four circuits shown in the figure, when the switch S is closed, the small bulbs L 1 and L2 can emit light normally, and the circuit diagram in which the voltmeter can directly measure the voltage across L 1 is ().

A. Figures A, B, B, C, C, D and D

Fourth, knowledge application questions (this question contains 7 small questions)

72.(04 Heilongjiang) After visiting the Science and Technology Museum, Xiaoming was deeply moved by a group of electrostatic experiments. When he came back, he drew the experimental scene as a plane schematic diagram, in which A is a positively charged ball on an insulating bracket and B is a positively charged ball suspended by an insulating silk thread. Hang the ball B at P 1 of P2 and P3 at different distances from the ball A (as shown in the figure).

What is the reason why the (1) ball deviates from the vertical direction?

Please ask a question according to this picture.

73.(04 Guilin, Guangxi) Ceramics, rubber, gasoline, glass, carbon pens, aluminum and other substances, of which _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ (fill in at least two kinds), choose two substances that you are most familiar with as electrical materials and explain their main functions.

①_______________________________;

②_______________________________.

74.(05 Fuzhou Curriculum Reform Area) Xiaohong's flashlight broke down while camping. Please help find out the reason.

(1) Please complete the circuit diagram according to the structural schematic diagram of the flashlight in the drawing.

(2) Write down three possible reasons why the flashlight doesn't work.

①____________________________________________________;

②___________________________________________________;

③__________________________________________________.

75.(05 Hechi, Guangxi) As shown in the figure,

(1) After closing the switch, the circuit will _ _ _ _ (fill in "path", "open circuit" and "short circuit");

(2) After the A line is removed, the circuit is a _ _ _ _ circuit;

(3) Change the connection of one of the three lines A, B and C to make the circuit a parallel circuit (put an "X" on the original line before changing the connection)

76.(05 Guangdong Province) The reading of the electric meter in the figure is: Figure A _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

77.(05 Anhui Province) When exploring the voltage relationship of series circuit, some students used the circuit as shown in the figure. He first measured the voltage at both ends of the bulb L 1 with a voltmeter. In order to measure the voltage across the bulb L2, he wants to connect the voltmeter to point A instead of point C in the circuit, while keeping the voltmeter at point B still. Do you think this connection is correct (choose "correct" or "incorrect"). The reason is.

78.(05, Chengdu, Sichuan (non-curriculum reform)) The resistance of the conductor is a property of the conductor itself, and its size depends on the material of the conductor, _ _ _ _ _ _ _ _ _ _ _ _ _. As shown in the experiment, AB and CD are both Ni-Cr alloy wires. This experiment is to study the resistance of conductor and _ _ _ _.

Five, information collection questions (this question contains 4 small questions)

79.(04 Changchun) The weather is dry. When combing the dry hair with a plastic comb, you will find that the hair floats with the comb, and the more fluffy it is. The physical knowledge involved here is: (1) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

80.(04 Dalian, Liaoning) The picture shows the circuit diagram of measuring the voltage across the resistor Rl with a voltmeter when studying the voltage relationship of the series circuit. There are two mistakes in this circuit.

(1) Please draw an "×" in the wrong place and correct it with a stroke line on the drawing.

(2) According to the modified physical diagram, draw the circuit diagram in the dotted box.

8 1. (Harbin, 05) is a circuit connected by a classmate as shown in the figure. (1) Please point out the error _ _ _ _ _ _ _ _ _ _ _ _ _ in the circuit.

(2) Change the circuit in the figure to the correct circuit. Only one wire needs to be replaced. Draw an "X" on the crossed-out conductor, and use a stroke line to represent the modified conductor if connection is needed).

82.(05 Guilin Curriculum Reform Area) adopted the method of "controlling variables" in the experiment to explore which factors are related to conductor resistance. The following table is a record of the related physical quantities of the conductors used by the experimental group in the experiment:

(l) To explore whether the conductor resistance is related to the length, two conductors should be selected _ _ _ _ _ _ _ _ _;

(2) To explore whether the conductor resistance is related to the cross-sectional area, _ _ _ _ _ _ two conductors should be selected.

6. Ask questions (this question contains 1 small questions)

83.(05 Wuhan City) In the circuit shown in the figure, except for one broken wire, the other equipment is intact. The power supplies of RL1=10Ω and RL2 = 5Ω consist of two new batteries. In order to find this wire, Xiaogang adopted the following methods: connect the positive terminal of the electric meter with the positive terminal A of the power supply, and then connect the negative terminal of the electric meter with the terminal B of L 1 and the terminal C of L2 respectively, and judge this wire by observing the instructions of the electric meter.

(1) Which of the following rice should Xiaogang choose before the above operation?

Voltmeter with a measuring range of 3V; B. voltmeter with range of 15V; An ammeter with a measuring range of 0.6A.

(2) After selecting the correct ammeter, when the ammeter is connected to point A and point B, if the ammeter has instructions, it must be disconnected; If the meter doesn't show numbers, the wire may be broken. When the ammeter is connected to point A and point C, if the ammeter has instructions, the conductor is not broken. At this point, the ammeter indicates.

VII. Drawing problem (this problem contains 1 item)

84.(05 Guiyang) According to the circuit diagram shown in Figure A, please connect the unconnected equipment in Figure B with brush wires instead of wires (wires cannot cross).

Eight, experimental design questions (this question contains 15 small questions)

85. According to the marked current direction, fill in the corresponding equipment symbols in 1, 2, 3, 4 and 5. Requirements: switch S 1 controls the whole circuit, switch S2 only controls the electric bell, and there is also a light bulb in the circuit.

86. As shown in the figure, the symbols of circuit elements are given, and the circuit diagram is connected according to the following requirements (the position of elements is fixed).

(1) In Figure A, L 1 is connected in series with L2, and the ammeter measures the current in the series circuit;

(2) In Figure B, L 1 and L2 are connected in parallel, the switch controls L 1, and the ammeter measures the main loop current.