(A) Clay
(B) Dry earth
(C) salt and charcoal mixed earth
(D) None of these
Answer (B)
2. How many meters from the building should the earthing electrode be installed, thereby earthing the installation system of the installation-
(A) 4.0
(B) 0.5
(C) 1.5
(D) 2.5
Answer - (C)
3. Loop strings used should not be less than the size of ............
(A) 8SWG
(B) 10 S W G
(C) 20SWG
(D) Half of the size of 14S WG or sub circuit wire
Answer - (D)
4. Earth wire or ground wire is made of-
(A) copper
(B) aluminum
(C) Iron
(D) galvanized
Answer - (D)
5. The purpose of earthing is-
(A) Providing possible low resistance from Earth
(B) Providing the highest possible resistance from Earth
(C) Providing positive, negative and zero sequence current flow
(D) None of these
Answer- (A)
6. According to ISI, the galvanized iron pipe minimum internal diameter for pipe earthing is-
(A) 19 mm
(B) 25 mm
(C) 32 mm
(D) 38 mm
Answer - (D)
7. The thickness of copper earth clectrode plate should not be less than ………
(A) 3.00 mm
(B) 3.15 mm
(C) 6.00 mm
(D) 6.3 mm
Answer (B)
8. Earth resistance can be reduced to acceptable levels by …………
(A) By increasing the size of Earth Electrode
(B) Earth electrode reduced by size
(C) By providing guards for the Earth Electrode
(D) by connecting multiple Earth electrodes in parallel
Answer - (D)
9. Equipment with earthing protects the device from …………
(A) leakage current
(B) break down voltage
(C) electric shock
(D) Operational surge voltage
Answer - (C)
10. The minimum size of plate electrode in plate earthing should be-
(A) 12.5X12.5 CM
(B) 20X20 CM
(C) 30X30 CM
(D) 60X60 CM
Answer - (D)
11. What is earthing?
(A) Connecting Electrical Machines to Earth
(B) Providing a connection to the ground
(C) Connecting electrical machines to the source
(D) To provide a source of current
Answer- (A)
12. What is an Earth Electrode?
(A) Electrode which is connected to Earth
(B) Used for Earthing
(C) the electrode connected to the circuit
(D) Electrode which is connected to Mains
Answer (B)
13. Earth electrode provides ____________
(A) high resistance
(B) medium resistance
(C) low resistance
(D) very high resistance
Answer - (C)
14. How is the position of the Earth electrode measured?
(A) by measuring the voltage
(B) by measuring the current
(C) by measuring the strength
(D) by measuring resistance
Answer - (D)
15. In the three phase system, neutral is _________.
(A) Earthed
(B) is connected to a low voltage
(C) is connected to high voltage
(D) Not connected
Answer- (A)
16. After earthing, various parts of electrical machinery are on _________.
(A) Infinite Potential
(B) Intermediate Potential
(C) Zero Potential
(D) Undefined Potential
Answer - (C)
17. Connection of different parts of a circuit to Earth is one
(A) medium resistance
(B) high resistance
(C) very high resistance
(D) very low resistance
Answer - (D)
18. Specific resistance of soil is _________.
(A) changes from soil to soil
(B) is stable
(C) depends on the circuit connected to it
(D) depends on the supply voltage
Answer- (A)
19. What is the uniqueness of GI earth plate?
(A) 60 cm * 60 cm * 3 mm
(B) 60 cm * 60 cm * 6 mm
(C) 60 cm * 60 cm * 4 mm
(D) 60 cm * 60 cm * 5 mm
Answer-(B)
20. What should be the amount of charcoal and salt for GI pipe earthing?
(A) Charcoal 5 kg, salt 8 kg
(B) Charcoal 10 kg, salt 8 kg
(C) Charcoal 10 kg, salt 10 kg
(D) Charcoal 5 kg, salt 5 kg
Answer-(C)