1. Xiaohong collected some examples related to mechanical energy in her studies, as shown in the figure, in which the mechanical energy increases ( )
A B C D
2. Regarding the relationship between heat, temperature, and internal energy, the following is correctly stated (
2) p>
A. The temperature of the object rises, the internal energy must increase B. The object absorbs heat, the temperature must rise
C. The temperature of the object remains unchanged, there must be no absorption of heat D. The temperature of the object rises, the heat must be absorbed
3. If the TV set, soldering iron and fan are labeled with the words "220V 60W", they are rated voltage work the same amount of time, the three The most heat produced by the three appliances is ( )
A. TV B. fan C. soldering iron D. as much
4. As shown in the figure, O is the fulcrum of the lever, the first lever in the action of the weight G and the force F1 is in the horizontal position of equilibrium. If the second lever is still in equilibrium under the action of weight G and force F2, the following relationship is correct ( )
A. F1>F2 B. F1=F2 C. F1 5. Xiaohua rode a study bike on a straight highway and drove at a constant speed with a normal speed with a power of 70W, then he rode his bike with resistance of about ( ) 6. About ( ) A, 2000N B, 200N C, 20N D, 2N 6. a bulb filament burned out, the broken filament lap together, the bulb will be brighter, the reason is ( ) A. filament resistance increases, the power increases B. filament resistance decreases, the power increases C. filament voltage increases, the power increases D. current in the filament increases, the power of the filament, the power of the filament, the power of the filament, the power of the filament, the power of the filament increases, the power of the filament, the power of the filament increases. D. The filament current increases, the power decreases 7. As shown in the circuit, the power supply voltage is unchanged, when the switch S is closed, the ammeter shows 0.8 amps; switch S is disconnected, the ammeter shows a change of 0.5 amps, then the ratio of the resistance of R1 and R2 ( ) A. 13:5 B. 3:5 C. 5:3 D. 5:13 8. p>8. Zhang Hua students in the investigation of the relationship between the current through the conductor and its voltage, the experimental data will be recorded by organizing the graph shown in the figure, according to the image, the following statements are wrong ( ) A. When the resistance of a certain current through the conductor a is proportional to the voltage on both sides of the conductor a. B. The resistance of the conductor a is greater than that of the conductor b. C. When the conductor a in the conductor b is greater than that of the conductor b. D. When two conductors a and b are connected in series to a power supply with a voltage of 3V, the current through the conductor is 0.2A 9. The figure shows the schematic diagram of the pressure transducer designed by Li, in which R1 is a sliding rheostat, and R2 is a fixed-value resistor. When the pressure F increases ( ) A current increases, the voltage decreases B current increases, the voltage increases C current decreases, the voltage decreases D current decreases, the voltage increases 10. The circuit shown in the figure, the power supply voltage is unchanged, close the switch S, the circuit works normally. After a while, the two electric representation are larger, the circuit failure may be ( ） A. lamp L short-circuit B. lamp L disconnect C. resistance R disconnect D. resistance R short-circuit 11. classroom next to the podium is equipped with an incandescent lamp and incandescent lamp control switch, the teacher needs to be installed in the podium a socket, the following is the installation of a number of students program, which is correct is ( ) A. from the incandescent light control switch on the two terminals were led out of the two wires will be socket access B. from the incandescent lamp head junction box on the two terminals were led out of the two wires will be access to the socket C. as shown in the figure: peeling a, b, respectively, will be two wires will be led to the socket access D. peeling a, c, respectively, will be two wires will be led to the socket access D. peeling a, c, respectively, will be two wires will be socket Access 12. The circuit shown in the figure, regardless of the effect of temperature on the filament resistance, the supply voltage remains constant. When in a, b indirectly "6V 6W" bulb L1, close the switch, the light L can be normal light; disconnect the switch, between a, b change access to a "6V 4W" bulb L2, and then close the switch, the following statements are wrong ( ) A. light L will become bright B. light L will dim C. change the connection to the light L2 may be burned D. circuit circuit is not a good idea, but it is a good idea. D. The total power of the circuit to become smaller Volume Ⅱ (***76 points) Two, fill in the blanks (1 point per blank, ***19 points) 13. "Shenzhou VI" launch phase accelerated upward, its gravitational potential energy (fill in the "increase", "decrease" or "unchanged"), the kinetic energy , mechanical energy . (Choose "increase", "decrease" or "unchanged"). 14. As shown in the figure, with a movable pulley pulling an object A to 0.5m / s speed in the horizontal plane of uniform motion, object A weighs 20N, by the friction is 0.2 times the weight of the object, the horizontal tension F is 2.5N, then in 2s the work done by the tension is ____ ___J, the mechanical efficiency of the pulley ___ ___ (not counting the pulley gravity). 15. When the voltage at both ends of a conductor is 3V, the current through it is 0.3A, then the resistance of the conductor is ________Ω; when the voltage at both ends of it is reduced to 1V, the current through it becomes _________A; when the voltage at both ends of it is 0, the resistance of the conductor is __________Ω. 16. In order to improve the urban Construction, Nantong City in the city intersections have been installed traffic red light, green light, yellow light and electronic police monitoring system. As shown in the figure shows an intersection of red light, green light, yellow light facilities. Known three bulbs are labeled "220V 100W", the three lights are _____________ joint, the facility will consume ____________kW-h of electricity in a normal working day (24h). 17. physical competition, Xiao Qiang in 20s on the completion of 10 pull-up movements, known as Xiao Qiang's weight of 500N, each action body upward movement of the distance of about 50cm, then Xiao Qiang in the whole process of work is about J, Small Qiang's power is about W. 18. a stove, in the connection with the home circuit voltage of 220V conditions, through the current 2.5A, then the stove is used for 10min, the current to do work ______J. This process *** have ______J of electrical energy into internal energy. 19. The voltage across a resistor changed 2V, the current from 0.4A to 0.6A, the resistance value of the resistor , the power of the resistor changed W. 20. Xiaojun's home in April, when the meter reading of the meter for the number of 4 2 5 3 0, May meter reading of the number of electricity as shown in the figure. Known as 1kW-h electricity costs 0.52 yuan, the Xiaojun family should be paid for electricity that month yuan. Xiaojun want to use the power meter to measure the power of an electric stove, so he will be connected to the electric stove in the home circuit, turn off the other appliances, measured in 10min the dial of the power meter turned 50 r, the power of the stove is W, the resistance of the electric stove is Ω. Three, graphing and experimental questions (***30 points) 21. The figure is the two resistors are connected in series schematic diagrams. Please draw the two resistors in the figure "equal sign" to the right of the total resistance of the series connection schematic, and in words that the total resistance of the series circuit is greater than the resistance of the series conductor reason ． 22. The figure is a lever, the direction of the known resistance F2, as well as the force arm of the power F1, in the figure to complete the force arm of F2, as well as the power F1. 23. As shown in the figure is a series circuit, a voltmeter and a single-pole, double-throw switch is correctly connected to the circuit, the requirements of the voltmeter can be measured with this voltage both the voltage of the terminals of the L1, but also can measure the total voltage of the terminals of the L1, L2. The total voltage across L1 and L2. 24. Figure for the measurement of the mechanical efficiency of the pulley block experimental device, the total weight of the hook code 6N. (1) the experiment to be vertically upward pulling the spring dynamometer, from the figure can be seen that the size of the pull force for N. If the hook code rise to a height of 8cm, the spring dynamometer upward cm, the mechanical efficiency of the pulley block for . (2) If only increase the number of hook yards, the mechanical efficiency of the pulley block will . (Select "increase", "decrease" or "unchanged") 25. Wang students in the "determination of the rated power of the small bulb" experiment, the power supply voltage of 3V, the rated voltage of the small bulb is 2.5V, as shown in the figure for the small Wang students have been connected to part of the circuit. (1) the connected circuit has two wires have not been connected, please help him to complete the circuit connection (other wires shall not be changed); (2) Wang students in checking the circuit is connected correctly, close the switch, found that the small bulb does not light, the voltmeter has a display and is 3V, the current is 0, the reason for this fault may be _____________________________; (3) Experiment Wang measured three sets of data in turn, and recorded in the table below, if the first experiment the ammeter display as shown in the figure, please read out this display and fill in the table, fill in the table, the data is _________A; Experiment order 1 2 3 U/V 2.0 2.5 3.0 I/A 0.40 0.42 Brightness gradually becomes brighter (4) The rated power of the small bulb is __________W; (5) In the experiment, Wang is moving the slide of the sliding rheostat to _________(fill in the word "left" or "right"); (6) The relationship between the brightness of the small bulb and the voltage is:; (7) According to the table above, the brightness of the small bulb is the same as the voltage. (7) According to the data and phenomena in the above table, the conclusion you can also summarize is: _______________________________. 26. A, B two students were to do the "determination of the power of the small bulb" experiment, in addition to the small lamps they use the same specifications of the equipment, the rated voltage of the small lamps may be "2.2V", "2.5V" or "3.8V", the power of the small lamps is not much difference. A students correctly connected to the circuit, closed the button recorded the first group of data, when the lamp normal light recorded the second group of data, move the slide to the end point of the lamp flashes, and then extinguished, and recorded the third group of data, as shown in the table below. The voltage of the power supply used by them is _______ volts, and the rated power of the lamp used by student A is ______ watts. When the small lamp chosen by student B is luminous, the voltmeter is shown in the figure, and the slide is exactly on the midpoint of the sliding varistor, the resistance of the sliding varistor connected to the circuit at this time is _______ ohms, and the current when the small lamp chosen by student B is luminous is ______ amperes. Physical Quantity Experiment No. Voltmeter Ammeter Ammeter Lamp Light and darkness 1 1.3V 0.16A Dark 2 2.5V 0.26A Normal light 3 4.5V 0A No light Figure 26 27. (7 points) Xiaoming has learned about the safe use of electricity, and would like to make a table lamp, he purchased A label is "36V 36W" bulb, after returning home in the installation, suddenly remembered that the voltage provided by the socket at home is 220V, so he looked for instructions in the box, but did not find, but found an accessory. (1) Xiaoming wanted to know the role of the accessory and its performance parameters (such as rated power, rated current, resistance, etc.), so he designed the circuit diagram shown in the figure and record data in the table, please help him according to the circuit diagram to complete the connection of the physical diagram. The number of experiments voltage current 1 9.2 0.05 2 18.4 0.1 3 36.8 0.2 (2) Xiaoming in the correct connection of the circuit, the measured experimental data recorded in the table on the right, according to the experimental data can be aware of the performance parameters of the accessory is (only required to write a parameter and its value). (3) Xiaoming with "36V 36W" bulb and accessories to make a desk lamp, please draw the circuit diagram of this desk lamp in the dotted line box, and explain the main role of accessories in the circuit is what Answer: . (Diagram 2 points + 1 point) (4) Do you think Xiaoming's homemade table lamp is reasonable? (Please briefly explain the reasons) (2 points) Four, answer the question (the answer to the necessary text description, formulas and calculations, *** 27 points.) 28, Xiaoming students at home on the electric stove to boil water found that the electric stove wire hot red, while the wire connected to the electric stove is not hot at all, this is why? 29. (6 points) resistance is a property of the conductor itself, its size is determined by the material, length, cross-sectional area of the conductor. Experiments have shown that at a constant temperature, the resistance of a conductor is directly proportional to its length and inversely proportional to its cross-sectional area. The resistance of a wire 1m long with a cross-sectional area of 1mm2 is called the resistivity of the material. If R denotes the resistance of the wire, l denotes the length of the wire, S denotes the cross-sectional area of the wire, and ρ denotes the resistivity of the wire, then ρ = ____________. (2 points) (1) The table below lists the resistivity of some materials at 20°C. If Xiao Hong is going to install a transmission line in her house, considering all factors, it is more appropriate to choose the material ___________. (2 points) (2) The resistance wire of the sliding varistor is made of nickel-chromium alloy. If a sliding varistor with a maximum resistance of 50 Ω is made from a nickel-chromium alloy wire with a cross-sectional area of 0.5 mm2, the length of the nickel-chromium alloy wire needed is _____________. (2 points) 30. (6 points) As shown in the figure, the lamp L1 is labeled "6V 3W", the lamp L2 is labeled "12V 4W", the switch will be closed after L1 is able to light up. (Do not take into account the effect of temperature on the resistance) to find: (1) voltmeter (1 points) (2) ammeter A2 (2 points) (3) the actual power of the lamp L2 and L2 energized for 1min of the heat generated. (3 points) 31. (7 points) An interest group uses the circuit shown in Figure A to carry out the following experimental study. (1) Close S1, disconnect S2, adjust the supply voltage, get the three sets of data in the table above. According to the data in the table, calculate the resistance value of resistor R. (Calculation results retained 1 decimal) (2 points) (2) Disconnect S1, close S2, adjust the supply voltage for the relevant measurements. According to the recorded voltage and current of the light bulb L data plotted as a voltage and current relationship image (Figure B). According to the image, when the voltage is 0.5V, how much power is consumed by bulb L in 50s? (3) When S1 and S2 are closed at the same time and the supply voltage is adjusted, what is the total power of R and RL when the power of bulb L is 1W? (3 points) 32. (6 points) Figure A is a small electric firing furnace circuit diagram, the heating element by eight sections of the same resistance wire, each section of the resistance value of the resistance wire are 4 Ω. Firing furnace is equipped with a high-temperature, low-temperature two gears, through the switch to achieve the switch between the two gears. The furnace temperature is monitored with a thermocouple-type thermometer, and Figure 32B is a schematic diagram of the work of monitoring the temperature of the furnace. Thermocouple thermometer principle shown in Figure C, two different conductors (such as platinum, nickel) each take one end connected together as a hot spot (J1 point) placed at high temperatures, the other end as a cold point (J2 point) placed at low temperatures, at low temperatures, A, B, between the two points will be the existence of a certain voltage, which is the thermocouple. The voltage of the thermocouple is known to be proportional to the temperature difference between the points J1 and J2. Therefore, if the temperature of the cold point J2 is known, the temperature of the hot point J1 can be determined from the reading of the voltmeter connected between points A and B. (1) Such a thermocouple is in effect a power source, and from what form of energy is its electrical energy converted? (2 points) (2) It is known that a platinum and nickel thermocouple thermometer produces a voltage of 1.5mV when the temperature difference between the hot and cold points is 100°C. What is the corresponding temperature in the furnace when the temperature at the cold point is 20°C and the voltmeter shows 12mV? (2 points) (3) If the power supply voltage used in the firing furnace is 220V, what is the electrical power of the high-temperature stage of the furnace? (2 points) Reference Answers I. Multiple Choice Questions AACCC BCBDA CA II. Fill in the Blanks 13. increase Increase Increase Increase Increase 14. 5 80% 15. 10 0.1 10 16. and 2.4 17. 2,500 125 3,300,000 3,300,000 19. 10 2 20, 78.26 1000 48.4 3. Graphing and Experimentation 21. increases the length of the conductor 24. uniform 2.4 24 83.3% increases 25. diagrams omitted bulb broken 0.36 1W left The higher the voltage, the brighter the bulb; the higher the power, the brighter the bulb. 26. 4.5 0.65 1W left The higher the power, the brighter the bulb. 26, 4.5 0.65 10 0.23 27, R = 184Ω role of voltage divider Reasonable: in line with the safety of electricity; unreasonable, resistance to consume electricity 28, according to the Q = I2RT wire resistance is very small, the heat generated is very little 29, SR / L copper 22.7M 30, 6V 0.3A 1W 60J 31, 10.0Ω 5J 1.625J 32, Internal energy into electrical energy 820℃ 2016.7W