Basic Electrical Engineering MCQ_53_1(Earthing)

Q.1 What are the objectives of earthing?
    A. It provides a path for discharging and de-energizing equipment to carry out maintenance on the equipment
    B. protection of human and animals life by controlling touch and step voltage to safer values
    C. It is used to provide zero potential surface
    D. all of the above
Ans.: D

Q. 2The process of connecting the metallic frame of electrical equipment or some electrical part of the system to earth is called____.
    A. Grounding or earthing
    B. earth resistance
    C. resistance of the earth electrode
    D. any of the above
Ans.: A

Q.3 The resistance of earth should be ____.
    A. low
    B. high
    C. the minimum possible
    D. infinite
Ans.: C

Q.4 The safety of electrical equipment and wiring is ensured by which of the following?
    A. earthing
    B. providing a fuse
    C. insulation
    D. All of the above
Ans.: D

Q.5 When moisture falls below _____, resistivity of earth increase sharply.
    A. 20%
    B. 40%
    C. 50%
    D. 10%
Ans.: A

Q. 6 Earth electrodes can be in the form of ____.
    A. pipe, plate
    B. strip
    C. wire
    D. all of the above
Ans.: D

Q. 7 Earthing is necessary to give protection against____.
    A. Electric shock
    B. voltage fluctuation
    C. over loading
    D. none of the above
Ans.: A

Q.8 The earth wire should not be size than
    A.20 SWG
    B. 10 SWG
    C. 25 SWG
    D. 5 SWG
Ans.: B

Q.9 The earth wire should be of ____.
    A. mechanically strong
    B. good conductor of electricity
    C. mechanically strong
    D. A and B
Ans.: D

Q. 10 On what basis the size of the earth wire is determine?
    A. current carrying capacity of line
    B. voltage of the service line
    C. Symmetrical fault
    D. any of the above
Ans.: A

Q.11 For domestic wiring, the minimum size of wire should be not less than
    A. 10 SWG
    B. 14SWG
    C. 20SWG
    D. 25 SWG
Ans.: B

Q. 12 Earth wire is made up of__.
    A. Copper
    B. Aluminium
    C. Galvanized steel
    D. Silver
Ans.: C

Q. 13 The earth potential is taken as___.
    A. high
    B. low
    C. infinite
    D. zero
Ans.: D   
Q. 14_____ site will be preferred for earthing.
    A. dry and rocky
    B. damp and wet sand pit
    C. clayey soil
    D. wet mashy ground
Ans.: D

Q. 15 which of the following is least preferred for earthing?
    A. earth mixed with salt and charcoal
    B. dry earth
    C. clayey soil
    D. all of the above
Ans.: B

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