1.(20 10 Shaoxing, Zhejiang, 32 questions) An experimental group explored the law of the resistance of a thermistor changing with temperature. The designed experimental device is shown in Figure A, and the main steps of the experiment are as follows:

(1) Add a proper amount of cold water into the beaker, connect the circuit correctly, close the switch, measure the voltage across the resistor R and the current through it, and turn off the switch. Fill the resistance value calculated according to ammeter, voltage indication and thermometer indication into the table;

② Add a small amount of hot water into the beaker, turn off the switch, measure the voltage across the resistor R and the current flowing through the resistor R, and turn off the switch. Fill the resistance value calculated according to ammeter, voltage indication and thermometer indication into the table;

(3) Repeat the operation of (2) several times to obtain multiple sets of data.

(1) Please use stroke lines instead of wires, and connect Figure B completely according to the circuit diagram in Figure A;

(2) The experimental data are as follows:

Figure C is the indication of ammeter and voltmeter in the fifth experiment. Please calculate the value of resistance r and fill it in the table.

(3) Please draw an R-T diagram in the graphic coordinates.

(4) According to the chart, the relationship between the resistance of the thermistor and the temperature is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

The number of experiments is 1 2 3 4 5.

Resistance r/ω1106145 35 _ _ _ _ _ _ _ _

Temperature t/℃

2. (Anhui, 2065 438+00 20) Measure the resistance of the unknown resistor RX with the circuit shown in the figure, and know the resistance of R0.

(1) Complete the experimental process:

A. Connect the circuit according to the circuit diagram, and slide the sliding vane of the sliding rheostat to the maximum resistance;

B. Turn off the switch, _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

C. Turn off the switch and tidy up the equipment.

(2) The symbols of the measured physical quantity and the known quantity are used to represent the measured resistance Rx = _ _ _ _ _ _ _ _ _ _ _ _

(3) Write the function of sliding rheostat in this experiment: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

3 (Shandong Weifang 20 10, 24 questions) A study group made exploratory experiments with sliding rheostat, two fixed resistors R 1, R2 (5Ω,10Ω), voltmeter, ammeter, power supply (6V), switches, wires and other equipment.

(1) Xiaoming's experimental group did an experiment to explore the relationship between the current on the resistor and the voltage at both ends.

Please help the group design a table to record the experimental data.

② The purpose of measuring several sets of data in this experiment is: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

(2) The following is a circuit diagram when exploring the relationship between the voltage across the series resistor R 1 and the voltage across R2 and the total voltage of the two resistors.

① Connect the unfinished physical drawings according to the circuit diagram. The wires should not cross, and the measuring range of the instrument should be selected correctly.

(2) If the circuit diagram is connected correctly and the ammeter is in good condition, but the sliding rheostat is adjusted anyway, and the ammeter has no indication and the voltmeter has indication, then the circuit fault may be (only answer one case): _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

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Pencil lead is made of graphite and clay. Different types of pencils have different soft and hard ranges of refills, among which pencil lead of 6H is the hardest, pencil lead of 6B is the softest, and pencil lead of HB is in the middle. Pencil lead is a conductor, so does the resistance of pencil lead have anything to do with hardness? Xiao Ming uses the device shown in figure 10 to explore this problem. He successively connected the pencil lead of 6B, HB and 6H between the two points of the circuit A and B. Through observation and comparison,

The magnitude of the resistance of the three. The basis for comparing resistances in this way is:

The three pencil lead he chose should meet the following conditions.

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4.(20 10 Yangzhou, Jiangsu, 29 questions) Xiaoming wants to explore the relationship between current and resistance in a circuit, and designs the circuit diagram as shown in Figure A (the power supply voltage is constant at 6V).

(1) Connect the physical drawings of Figure B with a pencil according to Figure A designed by Xiaoming.

Experimental serial number voltage /V resistance/ω current /A

1 4 10 0.4

2 20

(2) Xiao Ming fills the data obtained from the first experiment in the table on the right, then changes the resistance between E and F from 10ω to 20ω, and adjusts the slider P of the sliding rheostat to move (a/b) to _ _ _ _ _ _ _ _ _ _ _ _ _. At this time, the pointer position of the ammeter is shown in Figure C. Please fill in the measured current value in the above table.

(3) According to the experimental data, Xiao Ming draws the following conclusion: Current is inversely proportional to resistance. Please comment on the above inquiry process and write two comments: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _; ________________________________________。

5.(20 10 Yancheng, Jiangsu, 24 questions) do experiments with constant resistance to explore the relationship between the current passing through the conductor and the voltage across the conductor.

(1) As shown in Figure A, the experimental circuit is completely connected by the stroke line, instead of the wire, so as to maximize the resistance of the sliding rheostat connected to the circuit.

(2) Close the switch and move the rheostat slider to the left. The current indicator should be ▲ (select "Increase", "No Change" or "Decrease").

(3) Adjust the sliding rheostat, and fill in the measured data in the table below, where the current is 0.5A, the voltage is shown in Figure B, and its value is ▲ V. 。

The number of experiments is 1 2 3 4 5.

Voltage u/v 1.0 1.5 2.0-3.0.

Current I/A 0.2 0.3 0.4 0.5 0.6

(4) Draw the relationship between the current passing through the conductor and the voltage across the conductor in Figure C. 。

6. (Guilin, Guangxi, 20 10, question 27) As shown in figure 19, it is the experimental circuit connected by Xiaoming experimental group in the experiment of "measuring the resistance of small bulbs", and the small bulbs used are marked with the words "2.5V".

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(1) Please point out two improper points in the circuit connection: ①; ② 。

(2) After correcting the improper circuit connection, they closed the switch and moved the rheostat slider, and found that the readings of the two meters and the brightness of the bulb changed at the same time, but the readings of the two meters were always small, and the brightness of the bulb was very weak. The reasons for this phenomenon are:

(3) After the circuit was normal, they measured the voltage and current values of several groups of small bulbs respectively. The record is as follows:

(1) When the light bulb works normally, the resistance is about;

② According to the experimental data, the resistance of the small bulb is (fill in "constant" or "change") for the following reasons:

(4) At the end of the experiment, Xiao Ming put forward an idea: we can use the experimental equipment in Figure 19 to explore "what is the relationship between the main current and each branch current in parallel circuits".

Please help them design an experimental scheme and draw the circuit in the dotted box;

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② In the process of experimental exploration, the sliding rheostat can not only change the current in the circuit, but also be one of the circuits, but we must pay attention to it when moving the slider.

7.(20 10, Heze, Shandong, 20 questions) As shown in figure 13A, it is the physical connection diagram for Xiaohong to measure the resistance of small bulbs.

The power supply voltage of (1) is 6V. Please use brush wire instead of wire to help her complete the circuit connection.

(2) After the circuit is connected correctly, close the switch and find that the bulb does not emit light, the ammeter pointer does not deflect, and the voltmeter pointer deflects. Please help her find out the cause of the trouble (fill in the code name of the cause of the trouble below).

A, short circuit of small light bulb B, poor contact of power supply

C, small bulb open circuit D, ammeter internal short circuit

(3) After troubleshooting, close the switch, and the readings of ammeter and voltmeter are as shown in figure 13b, and then reduce the resistance of the light bulb.

Is ω.

8.(20 10 Zhenjiang, Jiangsu, question 29) Xiaoming is doing the experiment of "measuring resistance by voltammetry".

(1) According to the circuit diagram, the physical objects are connected by brush wires instead of wires, and the voltmeter is 0 ~ 3v.

(2) After closing the switch, it is found that the current represents zero and the voltmeter has obvious deflection, so the device for disconnecting the circuit is.

(3) Start the experiment after correcting the correctness of the circuit. The data of the previous two experiments have been filled in the table below. In the third experiment, the indication of ammeter is shown on the right. Please fill in the blanks in the table below. (The calculation result shall be kept to one decimal place. )

Experiment times current /A voltage /V resistance/Ω measurement result.

r =ω

1 0.30 2.5 8.3

2 0.26 2. 1 8. 1

3 1.6

(4) Xiao Ming wants to measure the resistance value (about10Ω) of a small light bulb with rated voltage of "3.8V" when it emits light normally. His experimental steps are: turn off the switch, remove the fixed resistor, connect the small light bulb marked "3.8V" to the position of the fixed resistor of the original circuit, and adjust the resistance value of the rheostat to the maximum; Adjust the off switch, and then move the slider until the light bulb lights normally. Read the ammeter and calculate the resistance of the bulb.

9.(20 10, Wuhan, Hubei, 13) Xiaoming uses the circuit shown in Figure A to explore the relationship between current and resistance. It is known that the power supply voltage is 6V and remains unchanged. The resistance values of the resistors used in the experiment are 5 Ω,10 Ω,15 Ω, 20 Ω and 25 Ω respectively.

(1) Please connect the physical circuit shown in Figure B completely according to Figure A (wires are not allowed to cross).

⑵ In the experiment, the resistance value of R was changed many times, the sliding vane of sliding rheostat was adjusted to keep the voltage indication unchanged, and the indication of ammeter was recorded, and the image of current I changing with resistance R as shown in Figure C was obtained.

① It can be concluded from the figure that when the voltage is constant,

(2) In the above experiment, after Xiaoming finished the experiment with a resistor of 5 Ω, the next operation was to connect the resistor of10 Ω into the circuit, close the switch, move the slider, and read the indication of the ammeter when the voltage indicator is V. ..

⑶ In order to complete the whole experiment, a sliding rheostat with maximum resistance not less than Ω should be selected.

10.(20 10? Hebei province, 34 questions) to explore the relationship between current and voltage and resistance.

What is the relationship between the current passing through a conductor and the voltage across the conductor and the resistance of the conductor?

Suppose (1) that the current passing through the conductor is proportional to the voltage across the conductor when the resistance of the conductor is constant.

② When the resistance of the conductor is constant, the current passing through the conductor is proportional to the square of the voltage across the conductor.

(3) When the voltage across the conductor is constant, the current passing through the conductor is inversely proportional to the resistance of the conductor.

The power supply of experimental equipment (constant voltage is 4.5 V), an ammeter and a voltmeter, a switch, three fixed-value resistors (5Ω,10Ω,15Ω), two sliding rheostats (20ω2a, 50Ω1a) and several wires.

Experimental process (1) According to the physical diagram shown in Figure 15, draw the circuit diagram in the dotted box.

(2) Xiao Ming connected the circuit correctly as shown in figure 15, and then turned on the switch, and found that the ammeter indicated that the voltmeter pointer was out of range. The mistake in Xiao Ming's operation is.

(3) Xiao Ming continued to do experiments after correcting his mistakes. By changing the voltage on the fixed-value resistor R, the measured values of current and voltage are shown in Table 1 By analyzing the data, we can draw a conclusion that the guess is correct.

Table 1 Table 2

Voltage u/v1.21.62.02.42.8 resistance r/ω 510/5.

Current I/A0.120.160.20 0.24 0.28 Current I/A 0.30 0. 15 0. 10.

(4) When Xiaohong explores the conjecture ③, first connect the 5 Ω resistor into the circuit, close the switch and move the slider, so that the voltmeter connected in parallel with the resistor indicates 1.5 V, and write down the current value; Then connect the resistors of10Ω and15Ω respectively, and repeat the above experiment to obtain the experimental data in Table 2. By analyzing the data, guess ③ is correct. In the experiment, Xiaohong moved the rheostat slider several times to.

(5) When exploring the conjecture ③, Xiaohua redesigned the circuit, kept the pointer of the voltmeter at 3 V, and obtained the same data as Table 2, thus completing the experimental exploration. The difference of Obana Xiaohong's experiment is that:

.

Knowledge expansion

(1) Xiaoming chose ω resistor in the experiment.

(2) The specifications of the rheostat selected for Xiaohong experiment are as follows. Quanpin middle school entrance examination network

1 1.(20 10 Laiwu, Shandong province, question 23) In the experiment of "measuring the resistance of small bulbs", there are the following equipment: voltmeter, ammeter, switch, power supply with voltage of 6V, small bulbs with "3.8V, 1.5W", and lamps marked with.

Jiayi

(1) Please use stroke lines instead of wires, and completely connect the physical circuits in Figure B according to the circuit diagram shown in Figure A (wires are not allowed to cross, and the ammeter range is properly selected);

(2) The students in Group A connected the last wire, and the light bulb immediately gave off bright and dazzling light, and soon went out. After checking, it is found that the connection is correct. Please find out two inappropriate operations in the experiment:

①___________________________________

②___________________________________。

(3) After the students in Group B turned on the switch, they found that the light bulb didn't light up, but the ammeter showed the numbers. What should be done next is.

A. replace the small bulb b and check whether the circuit is open.

C. Move the sliding blade of the sliding rheostat and observe whether the light bulb glows.

The number of experiments is12 3.

Voltage u/v 2.0 3.0 3.8

Current I/A 0.33 0.34 0.40

Resistance r/

6.0 8.8 9.5

(4) The following table is the data measured according to the correct operation. It is calculated from the table that the resistances of the three small bulbs are not equal, because _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

12.(20 10 Jixi, Heilongjiang, 27 questions) After exploring the relationship between the current on the resistor and the voltage at both ends, the students raised the question of what is the relationship between the current and the resistor. Please work with them to solve the following problems:

(1) The experimental circuit is completely connected with a stroke line instead of a wire. Quanpin middle school entrance examination network

(2) After the wiring is completed, before closing the switch, you should also

.

(3) After closing the switch, when moving the slider, it is found that the ammeter has no indication and the voltmeter has obvious indication. The reason for the failure may be.

Voltage U=2V

Degree 1 2 3

Resistance R/ω5 10 20

Current I/A 0.4 0.2 0. 1

(4) After troubleshooting, the students continued their experiments. After reading the current, some students directly removed the resistance of 5 Ω and replaced it with the resistance of10 Ω. He thinks this operation is simple and efficient. So,

(1) voltage said how will change?

(2) Please point out his mistakes in operation:

___________________________________。

(5) Analyze the experimental data in the table, please summarize the relationship between current and resistance:

.

13.(20 10 Yichang, Hubei, 32 questions) In the experiment to explore the relationship between the current on the resistor and the voltage at both ends, the equipment used is: a constant resistor R, a constant voltage power supply, an ammeter and a voltmeter, a sliding rheostat, a switch and several wires. Three students designed three circuit diagrams, A, B and C, as shown in Figure 9.

(1) Of the three circuit diagrams, only Figure C meets the requirements. The error in Figure A is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

(2) In these three circuit diagrams, there are sliding rheostats. For example, when the sliders P all move to the left, the indication of the voltmeter in Figure A will be _ _ _ _ _ _ _ _ in Figure B, the indication of the ammeter will be _ _ _ _ _ _ _ _ in Figure C, and the resistance value of the resistor R will be _ _ _ _ _. (Choose Bigger, Smaller, or Constant for all three spaces)

14.(20 10 Jingzhou, Hubei, 60 questions) Xiaoli uses the graphic circuit to explore keeping the voltage constant.

Relationship between current and resistance. When the resistance r1= 5 Ω ab, the voltage

The representation number is 6V; When ab = resistance R2 between10 Ω,

(1) The next operation after closing the key is (fill in "left" or "right").

Move the slider of the rheostat until;

(2) If the operation is correct, the total power consumed by the circuit when accessing R2 is higher than that when accessing R 1. (Select "Large" or "Small")

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15. (Question 23 of Meizhou 20 10, Guangdong) Zhou Xiao designed and connected the physical connection diagram as shown in figure 1 1 when doing the experiment to explore the relationship between current and resistance. Quanpin middle school entrance examination network

(1) Please draw the corresponding circuit diagram according to the physical connection in the question. Quanpin middle school entrance examination network

(2) In the experiment, Zhou Xiaoxian connected the 5 Ω resistor R to the circuit, and the circuit connection was completely correct. When the resistance of the sliding rheostat is adjusted to the maximum, the switch S is closed, and the indication of the ammeter is read directly, and the data is recorded in the table. Then replace the 5 Ω resistor with10 Ω and 20 Ω resistors respectively, and repeat the above operation. His mistake in the experimental operation is that he didn't keep the resistance r constant.

(3) Zhou Xiao re-conducted the experiment after discovering the error, and the data obtained are shown in the following table. According to the experimental data in the table, the conclusion is:

(4) Zhou Xiao found a small light bulb, so he replaced the 20 Ω resistor with this small light bulb and continued the experiment. As shown in figure 12, the resistance of the small bulb is ω.

physical quantity

Experiment times resistance R (ω Ω) current I.

(1)

1 5 0.48

2 10 0.24

3 20 0. 12

16.(20 10 Huadu District, Guangzhou, question 25) Xiao Nan wants to measure the resistance of a constant resistance.

(1)( 1) As shown in figure 16A, it is an experimental circuit designed by Xiao Nan. Please complete the unfinished physical circuit in Figure 15B with a stroke line instead of a wire according to Figure A, and ask the sliding rheostat to move to the left to increase the current representation.

(2) After connecting the circuit, Xiao Nan conducted an experiment, but due to Xiao Nan's negligence, after the experiment, it was found that all the measured current values were written on the draft paper and forgot to fill in the record form. Please help Xiao Nan fill in the current values recorded on the draft paper.

The number of experiments is12 3.

Voltage U/V 1.0 1.8 2.5

Current I/A

(3) After completing the above experiment, Xiao Nan wants to measure the resistance of a small bulb with a rated voltage of 2.5V with the original circuit. Xiao Nan replaced the resistor with a light bulb, closed the switch, and adjusted the sliding rheostat, and measured five groups of experimental data as shown in the following table:

Number of experiments voltmeter reading /V ammeter reading/bulb resistance/Ω average value of bulb resistance/Ω

1 0.5 0. 16 3. 13

R=

2 1.0 0.20 5.00

3 1.5 0.27 5.56

4 2.0 0.32 6.25

5 2.5 0.34 7.35

A. according to the above table, the rated power of the small light bulb is calculated as W.

Do you think her desk design is reasonable? Why?

C. According to the above experimental data, Xiao Nan draws the curve of the relationship between the current of the small bulb and the voltage at both ends, as shown in figure 17. As can be seen from the figure, the variation law of bulb resistance is as follows.

17. (Guangxi Liuzhou 20 10/0,30) Figure l4 is the experimental circuit diagram of Xiao Ming's research on the resistance of small light bulbs, and Figure l5 is the U-I diagram drawn by 1 according to the experimental data. The small bulb is marked with "2 V" and the sliding rheostat R is marked with "20 Ω1a".

(1) Before closing the switch, Xiao Ming should move the slider of the sliding rheostat to the _ _ _ _ _ _ end. In this experiment, the sliding rheostat is used to protect the circuit and _ _ _ _ _ _ _ _ _ _ _.

(2) Xiao Ming found that the light didn't light up after closing the switch, and the ammeter showed the number, but the voltmeter didn't. The reason for the failure may be

_________________________________________________________。

(3) When the light bulb normally emits light, the filament resistance is _ _ _ _ _ _ _ _ _ _ Ω: the whole product is tested in the network.

(4) Xiaohua, the deskmate, wanted to use Xiaoming's experimental equipment to measure the resistance of the unknown resistor, but found that the voltmeter was damaged and could not be used. He thought about it and borrowed a constant resistor R0, two switches and several wires from the physics teacher.

① Please use Xiaohua's existing equipment to design an experimental circuit diagram for Xiaohua, and measure the resistance of the unknown resistor in the right box (some circuits have been drawn);

② Write the expression of RX: Rx = _ _ _ _ _ _ _ _ _ _.

18.(20 10 Shanghai, question 26) In order to explore the relationship between current and voltage in conductors, Obana Xiaohai conducted experiments with two conductors, A and B. During the experiment, the voltages at both ends of the conductors were changed many times, and the measured data were recorded in Table 1 and Table 2. Quanpin middle school entrance examination network

○ 1 Analyze and compare the multiple relationship between current and voltage change in the experimental serial number 1, 2, 3 or 4, 5, 6, and draw a preliminary conclusion. For the same conductor, (13).

By analyzing and comparing the data of Experiment 3 and Experiment 5, they put forward a conjecture: under the same voltage, the current passing through different conductors is different.

1. In order to verify the above conjecture, based on the experimental data in Table 1 and Table 2, Xiaohua reset the voltage across conductor B and measured the corresponding current value. After analyzing Xiaohua's measurement data, Xiaohai thought that Xiaohua's measurement data was problematic, so he revised the data to measure. As shown in Table 3, you think Xiaohai's method of modifying data (14) is based on (15).

Ii. In order to verify the above conjecture, please combine the experimental data in Table 1 and Table 2 to analyze the shortcomings of the design in Table 3: (16).