Basic Electrical Engineering MCQ_55_1(Earthing)

Q.1 What is earth current?
    A. The current dissipated by the earth electrode into the ground
    B. the current at time of earth fault
    C. the current at which the protective system operated
    D. all of the above
Ans.: A

Q. 2 The current range of 1.6 mA, do not impain the person ability. It is also known as___.
    A. Fault current
    B. Let go current
    C. normal current
    D. none of the above
Ans.: B

Q.3 The body can tolerate _____ direct current than alternating current at 50 Hz.
    A. lower
    B. same
    C. higher
    D. can’t decide
Ans.: C

Q. 4 The current higher than ____ , dangerous for human body.
    Q. 10 mA
    B. 20 mA
    C. 100 mA
    D. 60 mA
Ans.: D

Q. 5 The current range of ____ , may be painful and affect person ability.
    A. 10-15 mA
    B. 9-25 mA
    C. 50-60 mA
    D. 100-150 mA
Ans.: B

Q. 6 The permissible current and duration should be less tha that required for ventricular fibrillation of the heart and is calculated by the following equation for up to 3 sec. (Person of 50 kg)
    A. IB= 0.116/√t
    B. IB= 1.16/√t
    C. IB= 116/√t
    D. IB= 11.6/√t
Ans.: A

Q.7 The lower the resistivity___ the earthing resistance.
    A. higher
    B. lower
    C. cannot change
    D. none of the above
Ans.: B

Q.8 Earthing of more than one point is used in ___ and higher voltage system.
    A. 32 kV
    B. 66 kV
    C. 220 kV
    D. 132 kV
Ans.: C

Q. 9 A coil type electrode, a coil of GI wire of ___ size is made.
    A. 5 SWG
    B. 14 SWG
    C.15 SWG
    D. 8 SWG
Ans.: D

Q.10 Resistivity of concrete becomes approximately equal to _____ Ωcm at 20ºC under the ground which is less than the average earth resistivity.
    A. 5000
    B. 1000
    C. 3000
    D. 2500
Ans.: C

Q. 11 Cross section area or the earthing lead should not be ____of the main conductor.
    A. more than
    B. less than half
    C. equal
    D. none of the above
Ans.: B

Q.12 The earth conductor which connects the main switch board to the distribution board is called as___.
    A. main earthing conductor
    B. sub earthing conductor
    C. Earthing leads
    D. any of the above
Ans.: B

Q.13 The earth wire which is run from the distribution board to different switch boards is called as the___.
    A. Earth electrode
    B. main earthing conductor
    C. Earth continuity conductor
    D. all of the above
Ans.: C

Q.14 The size of the earth continuity conductor should not be less than__.
    A. 14 SWG (2.894 mm2)         
    B. 28 SWG
    C. 15 SWG
    D. 8 SWG
Ans.: A

Q.15 The maximum permissible value of earth resistance for small substation is __.
    A. 5 ohms
    B. 10 ohms
    C. 20 ohms
    D. 100 ohms
Ans.: A

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