"Unit Error-prone Reinforcement Training" Life Electricity PPT

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"Unit Error-prone Reinforcement Training" Life Electricity PPT

Common mistake point 1: Unclear judgment of household circuit faults

1. In the home circuit as shown in the figure, the voltage between the live wire and the neutral wire should be 220 V. When the switch S is closed, the light bulb L does not light up. Use a test pen to test the neon tubes at three points a, b, and c. They all light up. Then use a test pen to test the two sockets of the socket. The neon tubes also light up. This circuit may have a problem. The fault may be ② (fill in the serial number).

①Short circuit inside the socket; ②Open circuit of the entry neutral line; ③Open circuit between wires bc

2. The light in the household circuit suddenly went out. Li Ming used a test pen to test the two transmission lines connected to the lamp head and found that the neon tubes did not glow. Based on this, it is inferred that the fault of the circuit may be (B)

A. Neutral wire disconnection B. Live wire disconnection

C. The bulb is broken D. The switch is short-circuited

3. A light at home suddenly goes out. Use a test pen (also known as a "test pen") to test four points a, b, c, and d in the circuit (as shown in the picture). Only when point a is measured, the neon tube emits light. If there is only one fault in the circuit, the fault may be (C)

A. The entry neutral line is broken B. The light bulb L is broken

C. Poor contact of switch S D. Open circuit of wire cd

4. Connect a lamp holder and a switch in series and connect it to the lighting circuit. It is found that no matter whether the switch is closed or open, the bulb on the lamp holder is always on. The reason for this phenomenon may be (C)

A. The live wire is directly connected to the lamp holder

B. The wire connector in the switch is loose

C. The joints of the two wires in the switch are in contact with each other

D. The joints of the two wires in the lamp holder are in contact with each other

5. As shown in the picture, the circuit of a bathroom in a family, the lights and the electric heater are working normally. When the washing machine is plugged into the three-wire socket (the switch is not closed), all the electrical appliances stop working. Unplug the washing machine. Finally, I used a test pen to test the left and right holes of the three-wire socket. The neon tubes both glowed, and it was found that a fuse was blown. Which of the following analysis is unreasonable (B)

A. The fuse on the neutral line must have blown.

B. Disconnect S1 and S2, and then use a test pen to test the left and right holes of the three-wire socket. The neon tubes will both glow.

C. Only disconnect S1, and then use a test pen to test the two terminals of switch S1. The neon tubes will both glow.

D. Only disconnect S2, and then use a test pen to test the two terminals of switch S1. The neon tubes will both glow.

Common mistake point 2: Unknown cause of electric shock in household circuits

6. As shown in the figure, an electrical appliance with a metal casing has three contacts (A, B, and C) (which can be connected or disconnected). During use, when a person stands on the ground and part of his body comes into contact with the metal shell, among the following three contact disconnection situations, the one most likely to cause an electric shock accident is (B)

A. Contact A: connected, contact B: connected, contact C: connected

B. Contact A: disconnected, contact B: connected, contact C: disconnected

C. Contact A: disconnected, contact B: disconnected, contact C: disconnected

D. Contact A: connected, contact B: disconnected, contact C: disconnected

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For more information about the PPT courseware "Reinforcement of Errors in the Unit of Electricity Use in Daily Life", please click the Intensive Exercise of Errors in the Unit of Electricity in Daily Life ppt tag.

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Update Time: 2024-07-01

This template belongs to Physics courseware People's Education Edition Ninth Grade Physics Complete Book industry PPT template

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