question bank source: Safety Production Mock Examination Yidiantong public account applet
The latest analysis of low-voltage electrician is a set of low-voltage electrician examination questions generated from the Safety Production Mock Examination Yidiantong general question bank, and the Safety Production Mock Examination Yidiantong is synchronized with mobile phones for low-voltage electrical work practise. The latest analysis of low-voltage electricians in 2021 and low-voltage electrician examination questions
. [Single-choice question] When using wire strippers, you should use a cutting edge that is larger than the wire diameter ( ). (B)
A, the same
B, slightly larger
C, larger
. [Single-choice question] There are many electrical appliances, including (). (B)
A, contactor
B, travel switch
C, thermal relay
. [Single-choice question] () is an essential protective device when working on a pole. It must be used in conjunction with a climbing plate or a foot buckle. (A)
A, safety belt
B, ladder
C, gloves
. [Single-choice question] The use of safety ropes should be (). (A)
A, high hanging and low hanging
B, low hanging calling
C, ensuring safety
5. [Single choice question] When the capacitor is found to be damaged or defective, you should ( ). (B)
A, repair
B by yourself, send it back for repair
C, discard
6. [Single-choice question] The unit of power of a capacitor is (). (A)
A, lack of
B, tile
C, volt-ampere
7, [Single-choice question] Dry powder fire extinguishers can be used to extinguish live fires on lines below ( )kV. (C)
A, 10
B, 35
C, 50
8. [Single choice question] The total capacity of each lighting (including fan) branch is generally not greater than ()kW. (B)
A, 2
B, 3
C, 4
9. [Single-choice question] Mobile mechanical equipment powered by a fixed power supply or a mobile generator should have a reliable metallic connection with the power supply ( ). (C)
A, shell
B, neutral line
C, grounding device
0, [Single choice question] Under normal circumstances, the resistance of the human body under the action of 220V power frequency voltage is ( ) Ω. (C)
A, 500 to 1000
B, 800 to 1600
C, 1000 to 2000
1, [Single choice question] The capacitor should ( ) after the pointer swings when checking with a multimeter. (B)
A, stay still
B, gradually swing back
C, swing back and forth
2. [Single-choice question] The wire cutters with plastic handles used by electricians have a withstand voltage of ( )V or above. (B)
A, 380
B, 500
C, 1000
3, [Single Choice Question] () The instrument has high sensitivity and accuracy, and is mostly used to make portable voltmeters and ammeters. (A)
A, magnetoelectric
B, electromagnetic
C, electric
4, [Single-choice question] The power supply of mobile electrical equipment should use high-strength copper core rubber sheath soft insulation (). (B)
A, wire
B, cable
C, stranded wire
5, [Single-choice question] The state stipulates ( ) operation categories as special operations. (C)
A, 20
B, 15
C, 11
6, [Single choice question] The thread of the screw lamp cap should be connected with (). (A)
A, neutral line
B, phase line
C, ground line
7. [Single-choice question] The sound of the motor during normal operation is smooth, brisk, ( ) and rhythmic. (B)
A, screaming
B, uniform
C, friction
8, [Single choice question] The insulation resistance of Class I power tools is required to be not less than ().(B)
A, 1MΩ
B, 2MΩ
C, 3MΩ
9. [Single choice question] When the protective grounding of low-voltage power supply lines and the building lightning protection grounding network need to be shared, the grounding network resistance requirements ( ). (B)
A, ≤2.5Ω
B, ≤1Ω
C, ≤10Ω
0, [Single choice question] The basic structure of the universal transfer switch contains (). (B)
A, reaction force system
B, contact system
C, coil part
1, [Single-choice question] The ultra-low voltage limit refers to the ( ) voltage value that appears between any two conductors under any conditions. (B)
A, minimum
B, maximum
C, middle
2, [Single choice question] The unipolar semiconductor device is (). (C)
A, diode
B, bipolar diode
C, field effect transistor
3, [Single choice question] The rated voltage of the fuse is the maximum operating voltage of the circuit specified from the perspective of (). (B)
A, overload
B, arc extinguishing
C, temperature
4, [Single choice question] Sometimes before using a clamp meter to measure current, the jaws need to be opened and closed several times for the purpose of (). (B)
A, eliminate residual current
B, eliminate residual magnetism
C, eliminate residual stress
5, [Single choice question] () The instrument consists of a fixed coil, a rotatable core and shaft, a hairspring, a pointer, a mechanical zero adjustment mechanism, etc. composition. (B)
A, magnetoelectric
B, electromagnetic
C, inductive
6, [Single choice question]
The following graphics, () is the electrical graphics of the button.
(A)
A,
B,
C,
7, [Single choice question]
The graphic symbol of the diode is.
(A)
A,
B,
C,
8. [Single-choice question] When selecting the sensitivity of the leakage protection device, avoid unnecessary actions caused by normal ( ) that affect the normal power supply. (A)
A, leakage current
B, leakage voltage
C, leakage power
9, [Single Choice Question] The composition of the travel switch includes (). (C)
A, coil part
B, protection part
C, reaction force system
0, [Single choice question]
The electrical diagram of the iron shell switch is (), and the text symbol is QS.
(B)
A,
B,
C,
1, [Single choice question]
The symbol of the current meter is ().
(B)
A, Ω
B, A
C, V
2, [Single-choice question] Low-voltage electrical appliances can be classified as low-voltage distribution appliances and () electrical appliances. (A)
A, low-voltage control
B, voltage control
C, low-voltage electric
3, [Single-choice question] The structure of the frequency-sensitive rheostat is similar to the three-phase reactance, that is, it is composed of three iron core columns and ( ) windings. (C)
A, one
B, two
C, three
4. [Single-choice question] The voltage range of the multimeter is 2.5V. When the pointer points to the ( ) position, the voltage value is 2.5V. (B)
A, 1/2 range
B, full range
C, 2/3 range
5, [Single choice question] Class II handheld power tools are equipment with ( ) insulation.(C)
A, basic
B, protective
C, double
6, [Single-choice question] The main cause of electro-optic ophthalmia is (). (C)
A, infrared
B, visible light
C, ultraviolet
7, [Single-choice question] Safety extra-low voltage of ()V should be used in particularly humid places. (C)
A, 42
B, 24
C, 12
8, [Single choice question] When the combination switch is used for reversible control of the motor, () allows reverse connection. (C)
A. It is not necessary to
B after the motor has stopped completely.
C. It must be done after the motor has completely stopped.
9. [Single-choice question] If the person who received an electric shock has stopped heartbeating and is breathing, respond immediately. Give first aid to those who suffer electric shock ( ). (B)
A, supine chest compression method
B, external chest cardiac compression method
C, prone back compression method
0, [Single choice question] "No climbing, high pressure is dangerous!" The signboard should be made as ( ). (C)
A, red letters on a white background
B, white letters on a red background
C, black letters on a white background and red edges
1, [Single choice question] For low-voltage distribution networks, when the distribution capacity is below 100KW, the grounding resistance of the equipment protection grounding should not be More than ( )Ω. (A)
A, 10
B, 6
C, 4
2, [Single choice question] The inside of the inductive fluorescent lamp ballast is (). (B)
A, electronic circuit
B, coil
C, oscillation circuit
3, [Single-choice question] Check the insulation of each winding of the motor. If the insulation resistance is measured to be zero, and no obvious burnout is found, drying can be carried out. Dry processing, at this time ( ) is powered on. (B)
A,
A allowed,
C not allowed,
4, [Single-choice question] The protective characteristics of the fuse are also called (). (B)
A, arc extinguishing characteristics
B, ampere-second characteristics
C, temporal
5, [Single-choice question] Low-voltage electrical work refers to the installation, debugging, operation, etc. of electrical equipment below ( )V. (C)
A, 250
B, 500
C, 1000
6, [True or False Question] RCDs with residual operating current less than or equal to 0.3A are high-sensitivity RCDs. (×)
7. [True or False Question] When starting with star-delta step-down voltage, the starting torque is 1/3 of the starting torque when using delta connection directly. (√)
8. [True or False Question] The bimetallic sheet of the thermal relay is rolled from a metal material with different thermal expansion coefficients. (×)
9. [True or False Question] The tensile strength of the wire connector must be the same as the tensile strength of the original wire. (×)
50. [True or False Question] The right-hand rule is used to determine the direction of the induced current generated when a straight conductor moves to cut magnetic lines of force. (√)
51. [True or False Question] In order to prevent electrical sparks, arcs and other ignition of explosives, explosion-proof electrical equipment with an explosion-proof electrical level and temperature group suitable for the environment should be selected. (√)
52. [True or False Question] Safety and reliability are the basic requirements for any switching appliance. (√)
53. [True or False Question] The action value and release value of the intermediate relay are adjustable. (×)
54. [Judgement Question] When testing live equipment with a ground voltage above 50V, the neon bulb low-voltage electroscope should show that there is electricity. (×)
55. [Judgement Question] From the perspective of overload, the rated voltage of the fuse is specified. (×)
56. [True or False Question] Shields are equipment screens installed to prevent workers from accidentally touching live equipment parts. They are divided into two types: temporary shields and permanent shields. (√)
57. [True or False Question] After the leakage switch trips, it is allowed to check the line by disconnecting the power and then sending it back on.(√)
58. [True or False Question] Automatic switches are manual electrical appliances. (×)
59. [True or False Question] When measuring current, the ammeter should be connected in series in the circuit under test. (√)
60. [Judgement Question] If the motor smells burnt when it is running normally, it means that the motor speed is too fast. (×)
61. [Judgement Question] When the lamp cannot reach the minimum height, the voltage below 24V should be used. (×)
62. [True or False Question] The splicing method can be used when single-strand conductors with small cross-sectional areas are connected flatly. (√)
63. [Judgement Question] Electric shock is divided into electric shock and electric injury. (√)
64. [True or False Question] When using a bamboo ladder for work, it is appropriate to place the ladder at about 50° to the ground. (×)
65. [True or False Question] The TT system is a system in which the neutral point of the distribution network is directly grounded, and the shell of the electrical equipment also adopts grounding measures. (√)
66. [True or False Question] The high voltage and dazzling white light generated by lightning strikes can cause damage to electrical devices, buildings and other facilities. Damage to power facilities or power lines may lead to large-scale power outages. (×)
67. [True or False Question] When using multi-stage fuse protection, the rated current of the subsequent stage melt is larger than that of the front stage, with the power supply end as the front end. (×)
68. [True or False Question] All bridges measure DC resistance. (×)
69. [True or False Question] Commonly used insulation safety protection products include insulating gloves, insulating boots, insulating partitions, insulating mats, insulating platforms, etc. (√)
70. [True or False Question] To measure the ground insulation resistance and phase-to-phase insulation resistance of the motor, a megohmmeter is often used instead of a multimeter. (√)
71. [True or False Question] When checking the capacitor, just check whether the voltage meets the requirements. (×)
72. [True or False Question] The clamp ammeter can be made to measure both AC current and DC current. (√)
73. [True or False Question] The direction of voltage is from high potential to low potential, which is the direction in which the potential increases. (×)
74. [True or False Question] When the temperature of the conductor remains constant, the current passing through the conductor is directly proportional to the voltage at both ends of the conductor and inversely proportional to its resistance. (√)
75. [True or False Question] Electrical special operations personnel should have a high school education or equivalent. (×)
76. [True or False Question] The installation height of concealed sockets in special places shall not be less than 1.5m. (×)
77. [True or False Question] Compared with water and metal, water has better conductivity. (×)
78. [True or False Question] The bending speed of the bimetallic sheet of the thermal relay is related to the size of the current. The greater the current, the faster the speed. This characteristic is called the proportional time limit characteristic. (×)
79. [True or False Question] If employees of enterprises and institutions engage in special operations without special operation certificates, it is an illegal operation. (√)
80, [True or False Question] When the combination switch is selected to directly control the motor, its rated current is required to be 2 to 3 times the rated current of the motor. (√)
81. [True or False Question] The insulation resistance of valve-type arresters operating below 10kV should be measured once a year. (×)
82. [Judgement Question] The discharge load of the capacitor cannot be equipped with a fuse or switch. (√)
83. [True or False Question] Universal relays can be made into various relays by replacing coils with different properties. (√)
84. [True or False Question] The high voltage and dazzling light generated by lightning strikes can cause damage to electrical devices, buildings and other facilities. Damage to power facilities or power lines may lead to large-scale power outages. () (×)
85. [Judgement Question] The larger the internal resistance of the voltmeter, the better. (√)
86. [True or False Question] The total voltage of a parallel circuit is equal to the sum of the voltages of each branch. (×)
87. [True or False Question] When the PN junction is forward-conducting, the direction of its internal and external electric fields is consistent.(×)
88, [Judgement Question] Electrical equipment defects, unreasonable design, improper installation, etc. are all important causes of fires. (√)
89. [True or False Question] The voltage when an insulator is broken down is called breakdown voltage. (√)
90. [True or False Question] When using the foot buckle to climb the pole, each step up and down the pole must make the foot buckle ring completely inserted into the pole and reliably buckle the pole before the body can move, otherwise it will cause an accident. (√)
91. [True or False Question] When the main switch is pulled down, the line is deemed to have no power. (×)
92. [True or False Question] Electrician pliers, electrician's knife, and screwdriver are the basic tools commonly used by electricians. (√)
93. [True or False Question] The components of the same electrical component are drawn separately in the schematic diagram, and text symbols must be marked in order. (×)
94. [True or False Question] After the wires are connected, the smaller the distance between the connector and the insulation layer, the better. (√)
95. [True or False Question] According to statistics from some provinces and cities, the number of electric shock accidents in rural areas is less than that in cities. (×)
96. [Judgement Question] The rated current of the melt must not be greater than the rated current of the fuse. (√)
97. [True or False Question] Breaking current capability is one of the main technical parameters of various types of knife switches. (√)
98. [True or False Question] The total resistance of several resistors connected in parallel is equal to the sum of the reciprocals of the parallel resistors. (×)
99. [True or False Question] People with Meniere's disease are not allowed to engage in electrical work. (√)
00, [True or False Question] For equipment with motors, before the motor is powered on, the auxiliary equipment, mounting base, grounding, etc. of the motor must be checked, and power can be used after they are normal. (√)
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