Find 10 junior high school physics and electricity experiment questions
Junior high school physics and electricity experimental test questions
Junior high school physics experimental test for entering college—Electricity (1)
1. Draw the circuit diagram based on the physical drawing shown in the picture.
2. Connect the following objects according to the circuit diagram shown.
Junior high school entrance physics experimental test—Electricity (2)
1. As shown in the figure It shows that there are two small light bulbs and a switch on the table. Their connecting circuits cannot be seen under the table. A classmate tried it. When the switch is turned on, both light bulbs light up. When the switch is turned off, both light bulbs light up. Extinguish. Whether these two small light bulbs are connected in series or in parallel, please write down your judgment method.
2. Please follow the following requirements for the existing light bulbs L1 and L2, switches S1 and S2, power supply and wires. Draw the circuit diagram.
Requirements: ① As long as S1 is open, even if S2 is closed, the light L2 will not light up. ② When S1 is closed and S2 is open, the light L1 will be on, but the light L2 will not light up. ③ When S1 and S2 are closed at the same time When, both lights L1 and L2 are on.
3. Two lights and a switch are connected to a constant power supply. First close the switch, then light A will light up, but light B will not light up. Then turn off the switch, then both lights A and B will light up. All lights shine, but light A is not as bright as before. Please draw a picture.
4. Two single-pole double-throw switches, a small light bulb, a battery pack, and wires. Please design a circuit. , so that both switches can turn on or off the light.
5. As shown in the figure, the dotted box represents a science and technology experimental field and duty room in a school. There are currently thin wires long enough ( The wire resistance is ignored), one small light bulb, one electric bell, one battery pack, one switch, and several wires. In order to prevent livestock from breaking into the experimental field, please use these materials to design an alarm circuit for the guards in the duty room.
Requirements: When the situation is normal, the lights in the duty room will be on and the bell will not ring; when livestock breaks in, knocking down the fence will break the thin wires, and the lights will be on and the bell will ring.
6. The voltmeter and current indications are 2.5 volts and 0.44 amps respectively. Please mark the pointer position and the selected terminal on the dial as shown in the picture.
7 , a voltmeter used for students' experiments, with two ranges of 3V and 15V. After judgment, the 3V range was selected to connect to the circuit, but the scale on the o-3V block was unclear and the experimental data could not be read from it, but the value could be read from the scale on the o-15V block as 11.5V. Then, the experimental record should be filled in.
8. To use the voltmeter correctly, you should pay attention to the following when using it:
(1) The voltmeter should be __________ connected in the circuit to measure the __________ at both ends of a certain part of the circuit. , the voltmeter must be connected to this part of the circuit.
(2) The "+" and "-" terminals must be connected correctly. The current must be ____________ from the "+" terminal For the voltmeter, start from the "-" terminal to _______ the voltmeter, which is the same as the use of the ________meter terminal.
(3) The measured voltage should not exceed the ___________ of the voltmeter. If the voltage value of the voltmeter is exceeded, the pointer of the voltmeter will be marked___________, or even___________ the voltmeter. When the measured voltage cannot be estimated in advance, the __________ method can be used to judge whether the measured voltage exceeds Measuring range. If the measuring range is small, be sure to use the small range for measurement (the pointer has the smallest error in the one-third to two-thirds area)
Junior high school entrance physics experimental test—Electricity (3)
1. Yangyang bought a fully enclosed lead-acid battery. From the nameplate, it can be seen that the battery's power supply voltage is 6 volts and the maximum operating current is 1A, but the "+" and "-" poles are not marked. Yangyang has come up with a way to identify the positive and negative poles of the battery (method 1 in the table below). Now please design two different experimental methods (the equipment used is not limited) to identify the positive and negative poles of the battery, and complete the following surface.
Required equipment and brief steps to identify the positive and negative poles of the battery
Method 1
Method 2
2. Use the picture below Experimental device to study the relationship between current intensity and voltage.
(1) Draw the circuit diagram of the experiment in the upper box.
Table 1: Experimental records when using wire AB
Voltage (volts) 2 4 6
Current intensity (amps) 0.4 0.8 1.2
Table 2: Experimental records when using wire CD
Voltage (volts) 2 4 6
Current intensity (amps) 0.2 0.4 0.6
Analysis From the experimental results, the experimental conclusion is: The intensity of current in the conductor ________.
(3) It is found from the experimental records that under the same voltage, the current intensity through wires AB and CD is different, indicating that different conductors have different _________ on the current.
(4) The resistance of wire AB is R? = ________ ohms.
3. In the circuit shown in the figure, a, b, c, and d are four terminals. If the light does not light up after closing the switch, it has been determined that the bulb is open or short-circuited. If it is not allowed to disassemble the circuit, please use a voltmeter or an ammeter to judge the fault respectively, and fill in the method and judgment results in the table below (fill in one method for each type of electricity meter
Meter method (where connected, switch opening and closing conditions) Phenomenon and conclusion
Ammeter
Voltage meter
4. As shown in the figure, voltage is used The circuit diagram of the meter measuring voltage. The range used by the voltmeter is unknown, but the pointer positions of V1, V2, and V3 are shown in Figures A, B, and C respectively. Then the readings of the voltmeters V1, V2, and V3 are V, respectively. At this time, the voltage across the lamp L3 is V.
Wire code A B C D E F G
Length (m) 1.0 0.5 1.5 1.0 2.0 0.5 1 . 5
Cross-sectional area (m m2) 3.0 0.8 1.2 0.8 3.0 1.2 1.2
Material Iron tungsten nickel chromium wire Iron tungsten nickel chromium wire aluminum
5. When doing the experiment of "study what factors are related to the resistance of the conductor", in order to facilitate the research, the controlled variable method is used, that is, two suitable wires must be selected each time wires, measure the current passing through them, and then compare them, and finally draw a conclusion.
(1) In order to study the relationship between the resistance of the conductor and the length of the conductor, the wires and (just fill in the code) should be selected.
(2) In order to study the relationship between resistance and conductor material, two wires should be selected for comparison.
(3) If two wires A and D are selected for testing, then. In order to study the relationship between the resistance of the conductor and When the indications of voltmeter V1 are 2V, 4V and 6V respectively, the corresponding indications of voltmeters V2, V and ammeter A are as shown in the following table:
(1) For the three voltmeters in the table After analyzing the data, the conclusion can be summarized as:
(2) Analyzing the data of voltmeter V and ammeter A in the table, the conclusion is:
Junior high school entrance physics experiment test - Electricity (4)
1. In the experiment of "using a sliding rheostat to change the current intensity", Figure -1 is a schematic diagram of the sliding rheostat, Figure -2 is the experiment Circuit diagram.
(1) If the terminals M and N are connected to the terminals A and C of the sliding varistor respectively, when the slider P moves to the right (that is, to point B), the ammeter will read. If _________, the indication of the voltmeter will________(increase, decrease or remain unchanged).
If a student connects the terminals M and N to the terminals A and B of the sliding rheostat respectively. On, when the slide P moves to the left (that is, toward point A), the ammeter and voltmeter indicate ______. (Fill in to increase, decrease or remain unchanged)
Figure-1 Figure-2
2. Use the following physical connection diagram to conduct the experiment of "changing the current intensity with a sliding rheostat".
(1) There is an error in the wiring in the picture. If it is not corrected and the switch is closed for experimental operation, the result will be: ____________________________
(2) Please correct the error in the wiring diagram. Mark "╳" on the wiring, and use strokes to connect the circuit in the correct way.
(3) After correcting the circuit, close the switch and adjust the slider of the sliding rheostat to reduce the current intensity of the circuit. At this time, the indication of the voltmeter will be _______________.
3. Use a resistance box as a fixed-value resistor and a sliding rheostat to change the current intensity. The circuit diagram and physical diagram are shown in the figure.
(1) Answer after observing the actual schematic diagram and circuit diagram:
(A) When the two copper plugs A and C are pulled out of the resistance box shown in the picture, the resistance value of the circuit is connected is ______ ohms.
(B) To make the current intensity in the circuit increase when the slider P of the sliding rheostat slides to the left, you can change the ______ among the four terminals a, b, c, and d on the sliding rheostat. _ or _______ two binding posts connected to the circuit.
(C) When the two copper plugs A and C are pulled out of the resistance box, the maximum current intensity in the circuit is _______ amperes, and the range of the ammeter should be ______ amperes; add in The maximum value of the voltage across the resistor box is ______ volts. The range of the voltmeter should be _______ volts.
(2) Draw lines instead of wires, and connect the physical diagrams correctly according to the circuit diagram.
Requirements:
(A) When the slider P moves to the left, the current in the circuit increases;
(B) The ammeter and voltmeter should have appropriate ranges.
4. When doing an experiment to study the relationship between the resistance of a conductor and its length, the device in the picture was used. The resistance wire AB is longer than CD. When AB is connected to the circuit, the ammeter indicates is I1. When CD is used to connect to the circuit, the ammeter's indication is I2, and I2>I1. (1) The conditions that the two resistance wires AB and CD should meet are: (2) Analyzing the experimental results, the conclusion is: .
5. A student used the circuit shown in the picture to study the relationship between the current passing through the conductor and the conductor resistance. R is a fixed-value resistor. The resistance of the fixed-value resistor he used in his first experiment was The value is R1. After closing the switch, record the ammeter reading as I1. In his second experiment, he only changed the fixed resistance value to 2R1. After closing the switch, he recorded the ammeter reading as I2. It was found that I2 6. In the experiment of "Measuring Resistance with Voltmeter and Ammeter": (1) The principle of this experiment is: ____________________________________________;
(3) Draw the experimental circuit diagram and mark the "+" and "-" terminals of the ammeter and voltmeter in the diagram.
(4) If the power supply is powered by 2 dry batteries in series, the resistance of the resistor to be measured is estimated to be 10 ohms. When wiring, the ammeter should use the ___ range, and the voltmeter should use the _____ range. If 3 dry batteries are used for power supply in series, the ammeter should use the _____ range and the voltmeter should use the _____ range.
7. When doing the experiment of "measuring resistance with voltmeter and ammeter", you are required to design a table and fill in the recorded and calculated data in the table. Please draw the form you designed in the space on the right below.
8. (1) As shown in the picture, please follow the circuit diagram on the left to correctly connect the voltmeter to the physical circuit on the right. Requirements: Use the 0-3 range of the voltmeter, and do not cross the connections.
(2) Close switch K. To make the light bulb brighter, the sliding piece P of the sliding rheostat should be moved toward the ______ end. (Fill in A or B)
Junior high school entrance physics experiment test - Electricity (5)
1. After classmate Zhang Yue did the experiment of "measuring resistance with a voltmeter and ammeter", I wrote the following lab report, read the lab report carefully, and answer the questions.
Experiment report
1. Experiment purpose: measure the resistance value of resistor R.
2. Experimental steps:
(1) Draw the experimental circuit diagram according to the purpose of the experiment.
(2) Connect the circuit according to the circuit diagram, and adjust the sliding rheostat R’ to maximize the resistance in the circuit.
(3) Turn on the switch and read the ammeter and voltmeter indications.
(4) Calculate the resistance of R based on the measured voltage and current values.
3. Experimental record:
Voltage=3.5V
Current=0.5A
Resistance=7Ω
4. Experimental conclusion: The resistance of the resistor R to be measured is equal to 7 ohms.
Answer the questions
(1) Do you think this experimental report is complete? If it is incomplete, the items that should be added are:
(A) ________. (B) ____________________.
(2) Judging from the experimental steps, the main flaw of the experiment is __________________ Therefore it is not precise enough.
(3) The role of the sliding rheostat in the experiment is:
(A) ____________________________________________.
(B) ____________________________________________.
< p> Note: When measuring resistance by voltammetry, since the ammeter and voltmeter themselves have resistance, connecting them to the circuit will inevitably change the voltage and current in the circuit, which will bring errors to the measurement results. As shown in the figure, there are two connection methods for measuring resistance by voltammetryAs shown in Figure A, due to the shunting of the voltmeter, the current measured by the ammeter is larger than the real current, so the measured resistance is smaller than the real resistance. , so this method is suitable for measurement when the resistance of the resistor is much smaller than the internal resistance of the voltmeter.
(Internal connection method)
As shown in Figure B, due to the voltage division by the ammeter, the voltage measured by the voltmeter is larger than the real voltage. Therefore, the calculated resistance is larger than the real resistance, so this method of understanding is suitable for resistors. Measure when the resistance is much greater than that of the ammeter. (External connection method)
2. In order to measure the resistance value of the missing resistor R2, a student designed a circuit to measure the resistance, as shown in the figure. It is known that R=16 ohms and R1=16 in the figure ohms, the supply voltage remains the same. When K1 is closed and K2 is open, and the slider P of the varistor is moved to the midpoint of ab, the ammeter reading is 1.0 amps; when K1K2 is closed at the same time, and P is moved to terminal a, the ammeter reading is 3.0 amps, and the test passes Calculation shows whether a certain value of P can be measured using this design.
3. There is a resistor RX whose resistance value cannot be seen clearly. Now we want to measure its resistance value, but we only have a battery pack, a voltmeter, an ammeter, a switch, and a A resistor R0 of known value, a sliding rheostat R/ and several wires. Please use appropriate equipment to measure the resistance of RX using three different methods, and complete the following questions as required.
Method 1:
(1) The equipment selected is ________________________________________
(2) Circuit diagram
(3) The main steps are :
(4) The expression of RX is ____________________. (Indicated by letters)
Method 2:
(1) The equipment selected is ________________________________________
(2) Circuit diagram
( 3) The main steps are:
(4) The expression of RX____________________. (Indicated by letters)
Method 2:
(1) The equipment used is ________________________________________
(2) Circuit diagram
( 3) The main steps are:
(4) The expression of RX is ____________________. (Indicated by letters)
4. As shown in the figure, (A) is a physical diagram of a single-pole double-throw switch, and its symbol is as shown in (B). Figure (C) is an example of the circuit control function of a single-pole double-throw switch. When S touches "1", bulb E1 emits light, and when S touches "2", bulb E2 emits light. The following equipment is available:
A power supply (the voltage between the two poles remains unchanged, but the voltage value is unknown) A resistance box (represented by R0)
A voltmeter (the maximum range is greater than the power supply Voltage between two poles) A resistor to be measured (represented by RX)
A single-pole double-throw switch with several wires
(1) Based on the equipment given above, design a It can measure and calculate the standard circuit diagram of the resistance RX to be measured (it cannot be disassembled during the experiment after being connected).
(2) Write down the steps of measurement and the physical quantities measured.
(3) Write the expression to calculate RX using the measured quantity: .
Junior high school entrance physics experiment test - Electricity (6)
1. There is an ammeter G, internal resistance Rg = 10Ω, full bias current I = 3mA, and the ammeter is modified to have a range of 3V How big a resistor R is connected in series with the voltmeter?
2. There is an ammeter G with internal resistance Rg = 25Ω and full bias current I = 3mA. If it is modified into an ammeter with a range of 0.6A, how big a resistor should be connected in parallel?
Junior high school entrance physics experiment test - Electricity (7)
1. There are two fixed-value resistors R1 and R2 with equal resistance. One has a supply voltage of U and remains different. A new battery pack and some wires. Try out the above equipment and design two different connection methods, which are connected to the relevant terminals marked A, B, C, and D in the dotted lines A and B in Figure 1, so that they each form a complete circuit, and Make sure that both circuits A and B can meet the following three requirements at the same time:
(1) Correctly connect the battery pack between terminals A and D;
(2) When the switch S in the figure is turned off, the pointer of the ammeter deflects to a certain position (assuming the indication at this time is I);
(3) When the switch S in the figure is turned on, the indication of the ammeter It becomes twice the value when switch S is turned off (i.e. 2I).
2. A student used the power supply, ammeter, voltmeter, switch, sliding rheostat marked with "50Ω, 12A" and some wires to measure the rated power of the small light bulb. The words "0.3A" marked on the light bulb are clearly visible, the 0-15V range of the voltmeter is damaged, and the rated power of the small light bulb is estimated to be about 1.5W. The student's experimental steps are correct. When the switch is closed, the readings of the voltmeter and ammeter are 2V and 0.2A respectively. Then he thought and experimented until the small light bulb glowed normally. At this time, the slide of the sliding rheostat was exactly at the midpoint (that is, the resistance of the sliding rheostat connected to the circuit was 25Ω).
(1) Draw the circuit diagram of the small light bulb when it lights up normally, and briefly describe the reasons for judging that the small light bulb lights up normally.
(2) Find the rated power of the small light bulb.
3. The picture is a circuit diagram for measuring the rated power of a small light bulb with a rated voltage of 3.8 volts. The rated power is less than 2 watts (requires the correct selection of the range of the voltmeter and ammeter)
(1) Please follow the requirements of the circuit diagram to correctly connect the circuit components shown in the picture with pen-drawn lines as wires.
(2) Fill in the brackets with the serial numbers of the following experimental steps (1, 2, 3, 4, 5, 6) in a reasonable order in the experiment:
〔 〕Read Output the indication of the ammeter
〔 〕Close the switch
〔 〕Move the rheostat slide to the position with the largest resistance value
〔 〕Open the switch , connect the circuit according to the circuit diagram
〔 〕Fill the measurement data into the table and calculate the rated power of the small light bulb
〔 〕Move the rheostat slider so that the voltmeter reads 3.8 volts
(2) When a student was connecting a sliding rheostat, due to a wiring error, the sliding plate P of the sliding rheostat could not change the brightness of the small bulb when it moved. Based on the following two situations, please judge how the student is connected?
The first situation: when the small bulb is brighter, he connects the end points of the two wires to the sliding rheostat respectively.
The second situation: when the small bulb is dim, he connects the end points of the two wires to the sliding rheostat respectively.
4. The rated power equipment for measuring small light bulbs includes: small light bulb (rated voltage is 6V, maximum allowable current is 0.3A), an ammeter (range 0-0.6A and 0-3A, an Voltmeter (range 0-3V-15V), one 4V, 6V, 8V, 10V power supply, one sliding rheostat, one switch, and several wires
(1) Draw the experimental circuit diagram and label it. Output the positive and negative terminals of the ammeter and voltmeter (draw the circuit diagram in the box on the right)
(2) The power supply should be ____V, the ammeter range should be _______, and the voltmeter range should be _. ___.
(2) Before closing the switch, the sliding piece P of the rheostat should be placed at the _______ end (fill in a or b). During the experiment, the function of the rheostat is _______
(3) When the light bulb emits light normally, the voltage across the light bulb should be _______ volts. If the ammeter indicates as shown in the figure, the current intensity through the light bulb is _______ amperes, and the rated power of the light is _______ watts.
(4) During the experiment, it was found that the light bulb glowed, but b had a reading but a had no reading (zero). The fault may be ____________________
(5) Due to an incorrect connection to the circuit, a classmate found that the indication on one meter increased while the indication on the other meter decreased when moving the contacts of the sliding rheostat. The fault may be _______________
5. When a student was doing an experiment to measure the electric power of a small light bulb, his physical connection was as shown in the figure.
(A) In this physical connection diagram, the wiring error is: (It is not required to correct it in the diagram).
a)____________________________,
b)____________________________,
c)____________________________.
(B) If after correcting the connection error and adjusting the sliding rheostat, the voltmeter and ammeter readings are 2.2 volts and 0.2 amps respectively, then the actual power of the small light bulb is __________ watts.
6. In order to measure the power of a small light bulb with a voltage of 2.5 volts and a rated power of about 1W, the following equipment is available: A. Power supply (2V); B. Power supply ( 6V); C, ammeter (0~0, 6A); D, ammeter (0~3A); E, voltmeter (0~3V); F, voltmeter (0~15V); G, maximum resistance 5 ohms Rheostat; H. Rheostat with maximum resistance of 15 ohms; I. Electric key; J. Several wires.
(1) What equipment should be used in the experiment (fill in the serial number)
The data measured by a student during the experiment is as follows.
When sorting the data to calculate the power, I found that the results of one experiment were very different from the results of the other two experiments. After inspection, it turned out that one of the current intensity indicators had been read incorrectly. The ammeter the student chose has a range of 0-0.6 amps. Trial analysis:
(1) The current intensity reading for the _________th time in the data table is wrong, and the correct one should be _____________.
(2) The _______________th time What the experiment measured was the rated power of the small light bulb.
(3) Rated power P of small light bulb =__________.
Times voltage (volts) Current intensity (amps)
1 2.00 1. 00
p>2 2.50 0.25
3 3.00 0.30
7. In the experiment of "determining the power of a small light bulb with a rated voltage of 2.5V", the students followed the steps shown in the figure Connect the equipment to the circuit diagram shown and conduct the experiment.
(1) Adjust the slider of the sliding rheostat. When the small bulb lights up normally, the ammeter reads O. 3A, the power rating of the small light bulb is w.
(2) If the power supply voltage is 6V and the sliding rheostat has two specifications: "10Ω, 1.5A" and "20Ω, 1A", then the sliding rheostat with specifications should be selected in this experiment.
(3) After wiring, a classmate found that the light bulb was already lighting up when the switch was not closed, and the electrical indicator was normal. However, after the switch was closed, the light bulb went out, the voltage indicator decreased to zero, and the current indicator changed. Large, but not beyond the range. What do you think is the error in his wiring?
(4) Another student completed the circuit connection and closed the switch. When adjusting the rheostat slide, he found that the voltmeter indication decreased when the bulb became brighter and increased when the bulb dimmed ( The equipment is in good condition). Think about it, how to connect the circuit to cause this phenomenon?
8. Use an electric energy meter and a stopwatch to measure the power of electrical appliances
The principle of this experiment is ＿＿＿＿＿Among them, the electric energy meter Used to measure ＿＿＿＿＿＿Stopwatch used to measure ＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿ The electric energy is n/3000 * 1KWh
Example: The household electric energy meter is marked with "2500 R/KWh". If an indoor electrical appliance unit works for 30 minutes and the turntable rotates 50 times, then the electric energy meter should be used An electrical appliance consumes 1 kilowatt hour when working for __________ hours, and the power of this electrical appliance is __________ watts.
Junior high school physics experiment test - Electricity (8)
1. According to the conditions given in each picture in the picture, draw the winding method of the solenoid coil on the picture.
2. In Figure a, when K is closed, conductor AB will move to the right in the magnetic field.
This is because the conductor is _____. In Figure b, when conductor AB moves to the right, the pointer of ammeter G will deflect. This is a _____ phenomenon.
3. In the device as shown in the figure, when conductor AB moves upward or downward in the magnetic field,
The ammeter pointer ______; when conductor AB moves forward or backward When, the pointer
_______. (Fill in "deflection" or "non-deflection")
4. In the experiment to study electromagnets, you will be given two electromagnets with different numbers of coil turns, power source, shape, sliding rheostat, ammeter and an Xiaodui Pin Question:
(1) The function of the pin is to observe ＿＿＿＿＿＿＿＿＿＿＿＿
(2) The function of the sliding rheostat is ＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿ _
(3) The power supply, switch, sliding rheostat and two electromagnets with different coil turns are connected in series to conclude that when the current intensity is the same, the magnetic strength of the electromagnet is related to __________.
(4) The magnetism of the electromagnet is made based on the principle of __________. One of its applications is the air switch, electromagnetic crane, and the iron core of the electromagnetic crane is applied __________.
5. Please design an electromagnet with adjustable magnetic field strength, draw the circuit diagram and briefly explain it.
11. As shown in the figure, iron block B is hung under the spring. C is the solenoid, and it is directly below B. After closing the switch K, the upper end of the solenoid is the ________ pole. When the copper plugs on the resistance box are pulled out in turn, the ammeter reading will be ________, The length of the spring will _________.
6. Install the DC motor model
Example: (1) During the experiment, after the assembly is completed, close the switch and the coil will not rotate. If you push the coil lightly with your hand, the coil will rotate rapidly. When it rotates, the reason why the coil does not rotate is () If the coil is sometimes fast and sometimes slow, the reason is ()
A. The brush and commutator are in poor contact.
B. The magnet is not magnetic
C. The positive and negative terminals of the power supply are reversed D. The coil is just in the balanced position
(2) If you want to change the direction of the installed motor, you can take The measures include _______________ and _______________.
(3) If a strong magnet is replaced, the observed phenomenon is __________________.
If the slider of a varistor is moved so that the resistance of the connected circuit increases, the observed phenomenon is ____________________________