A. the plastic comb lost some electrons. Plastic combs get some electrons.
C. the hair gets some electrons. There is no electronic transfer between hair and comb.
2. (Huangshi City) It is known that three charged balls A, B and C attract each other, while B and C repel each other. If ball A contacts uncharged metal ball D, and then ball D approaches ball C, then balls C and D will ().
A. Mutual attraction B. Mutual repulsion C. Neither attraction nor repulsion D. The above situations are possible
3. (Taizhou) of the following objects, which belongs to the insulator is ()
A. iron wire B. copper wire C. pencil lead D. porcelain rod
4. (Yueyang City) Three charged or uncharged balls A, B and C, it is known that A and B repel each other and B and C attract each other. If b is positively charged, then ()
A.A must be negatively charged B.C. must be negatively charged C.C. may not be charged D.A. may not be charged.
5. (Henan Province) Usually, in the following group of substances, the insulator is ()
A. air, plastic, human body B. ceramics, wet wood, rubber
C. Air, oil and plastics D. Glass, oil and soil
6. (Yongzhou senior high school entrance examination) In general, the following groups of objects are all conductors:
A. rubber, glass B. oil, soil C. soil, ceramics D. graphite, aluminum
7. (Jilin) Under normal circumstances, the following substances are easily conductive:
A. plastic b glass c rubber d graphite
8. (Jingzhou City) Among 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.
9. (Huanggang City) As shown in the figure, when a negatively charged object A touches the metal ball B of the uncharged electroscope, the metal ball B is also negatively charged, so ()
Some electrons on a.a are transferred to b, and the instantaneous current direction is b → a.
Part of the electrons on B. B are transferred to a, and the instantaneous current direction is a → b.
Some positive charges on C. B are transferred to a, and the instantaneous current direction is b → a.
Some positive charges on D. A are transferred to b, and the instantaneous current direction is a → b.
10. (Lanzhou) In the circuit shown in the figure, the switch S can control the lamp and the bell at the same time ().
1 1. (Changde) Regarding conductors and insulators, the following statement is correct ().
A. Under normal circumstances, metal, human body, earth and ceramics are all conductors;
B, insulator is not conductive, because there is no charge in the insulator;
C, the conductor is easy to conduct electricity, because there are a lot of movable free electrons in the conductor;
D, there is no absolute boundary with insulator;
12. The following statements about conductors and insulators are correct: ()
A. A conductor can conduct electricity because there is a lot of charge in it. Insulators do not conduct electricity easily 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.
1. (Chengdu senior high school entrance examination) Rub the glass rod with silk, and the glass rod is positively charged because of ().
A. triboelectrification generates charge b, and the positive charge on the wire is transferred to the glass rod.
C. the electrons on the wire are transferred to the glass rod d, and the electrons on the glass rod are transferred to the wire.
2. (Lanzhou) About the physical connection diagram in the diagram, as shown below.
The correct statement is ()
A.l 1 and L2 are connected in series. B.l 1 and L3 are connected in series.
C.l 1, L2 and L3 are connected in series; D.l 1, L2 and L3 are in parallel.
3. As shown in the figure, when the switch K 1 K2 is closed, the circuit
A, Three Lamps District, and all on.
Three Lamps District are connected in series, and they are all very bright.
C, L 1L2 and L3 are connected in parallel, and all three lights are on.
D, L 1 L2 is connected in parallel, L3 is short-circuited, and only L 1L2 is on.
4. (Senior high school entrance examination in Chengdu) In each circuit as shown in the figure, after the switch S is closed, the small bulbs L 1 and L2 can emit light ().
5. (Yueyang City) After the circuit switch is closed as shown in the figure, the following statement about this circuit is incorrect ().
A. the current direction in the circuit is as shown in the figure.
B.l 1 and L2 belong to parallel connection.
C. the switch s can control the whole circuit.
D if the two ends of L 1 are directly connected by wires, L 1 will emit L2 light.
6. (Jiangxi Province) In the circuit shown in the figure, when switches S 1 and S2 are closed, the following statement is correct ().
A. only L 1 glows. Only L2 will emit light. C. l 1 and L2 both emit light. D. l 1 and L2 do not emit light.
7. (Yongzhou, senior high school entrance examination) The symbols of the following circuit components are incorrect: ()
8. (Nanchang senior high school entrance examination) When the charged glass rod is close to the positively charged light ball, the interaction is shown in the figure. From this, it can be judged that the glass ribbon _ _ _ (fill in "positive" or "negative") is because _ _ _ charges repel each other (fill in "same" or "different").
9. (Nanjing, senior high school entrance examination) The glass rod rubbed with silk is positively charged because there are _ _ _ electrons in the glass rod when rubbed (choose "gain and loss"). The instrument commonly used in the laboratory to test whether an object is charged is _ _ _ _.
10. In the circuit shown in the figure, when S 1 is disconnected from S3 and S2 is closed, L 1 and L2 _ _；; When S2 is off and S 1 and S3 are closed, L 1 and L2 _ _ If S 1, S2 and S3 are closed at the same time, it will lead to circuit _ _.
1 1. (Yancheng) In the circuit of Figure 4, it is only connected to _ _ _ _ _ _ when it is closed; When closing and disconnecting, use _ _ _ _ _ _ _ to connect; Turning off,, and at the same time will result in _ _ _ _ _.
12. (Fuzhou) We often see an eye-catching slogan "It is forbidden to transport gasoline in plastic barrels" at gas stations. This is because the gasoline in the barrel will constantly rub against the barrel wall, causing the plastic barrel to carry _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
13. (Changde, senior high school entrance examination) The fur rubbed with glue sticks is charged, which is because fur electrons (fill in "gain" or "loss") during the rubbing process.
14. (Xianning City) As shown in the figure, when the glass rod rubbed with silk touches the metal ball of the electroscope, you will see that the two metal foils that were originally closed will be _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.
1. (Gansu Province) Physical achievements are widely used in the military. A weapon called graphite bomb was used to destroy the enemy's power supply facilities in the war. This kind of bomb will not cause casualties, but it will spread a lot of extremely fine graphite wires in the air. These graphite wires are _ _ _ _ _ _ _ _ (fill in "conductor" or "insulator"); Falling on the power supply equipment will cause _ _ _ _ _ _. (Optional "open circuit" or "short circuit") to disable the power supply system.
2. (Wuhu City) The following are six common substances in life; Iron, glass, crystal, salt water, mercury, biscuits. Please divide them into two categories; One category includes: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ and so on
3. (Anhui Province) As shown in the figure, add salt water into a beaker, and then insert the steel sheet and zinc sheet connected to the voltmeter into the salt water to make the battery. Observing the deflection and wiring of the voltmeter pointer, we can know that the voltage of this battery is _ _ _ _ _ V, and the _ _ _ _ _ piece is its positive electrode.
4. In the circuit in the (Yancheng) diagram, L 1 and L2 _ _ _ _ _ _ _ _ are turned on only when S2 is closed; Close S 1 and S3, and disconnect S2, and L 1 and L2 _ _ _ _ _ _ _ _ _； When S 1, S2 and S3 are closed at the same time, the phenomenon of _ _ _ _ _ _ _ will occur.
5. (Nanjing) Students in an interest group can draw the conclusion that the compressor and the light bulb are connected together after the refrigerator door is opened according to the phenomenon of _ _ _ _ _ _ _ _ _.
6. (Sichuan Province) In the picture, A is a metal wrench and B is a pair of bamboo chopsticks. Please: (1) Write the difference between them from the perspective of mechanical knowledge: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. (2) From the perspective of electrical knowledge, write the difference between them: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.
7. (Jingzhou) Two SARS patients were isolated in two separate wards of a hospital. In order to facilitate the contact between patients and medical staff, please design a circuit and draw a circuit diagram with the given equipment according to the following requirements.
Equipment: a power supply, two switches, an electric bell, a red and green light bulb, and several wires.
Requirements: Patient A turns off the switch, the red light is on, and the electric bell rings. Patient B turns off the switch, the green light is on, and the bell rings.
8. (Gansu Province) There is a desk lamp that can continuously adjust the brightness of light bulbs. Now we provide you with the following equipment: a battery pack, a small light bulb, a sliding rheostat, a switch and several wires. Please design a circuit diagram in which the light bulb can be dimmed continuously (from the darkest light bulb to the brightest light bulb).