Electrical Quiz MCQ - Set 09

Quiz Questions

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01. To ensure safe isolation, voltage indicating devices

     (A) Must comply with BS 7671

     (B) Are used to prove the circuit dead only

     (C) Are used to prove the circuit was alive only

     (D) Must be ‘proved’ prior to and ‘re-proved’ after isolation

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02. Relevant information for re commissioning street furniture can be found in

     (A) IEE Guidance Notes 7

     (B) Works instructions

     (C) The Electricity Supply Regulations

     (D) The Petroleum (Consolidation) Act 1928

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03. Before any work is done within an electrical installation, the first procedure would be to

     (A) Carry out a risk assessment

     (B) Turn off the main switch

     (C) Remove all components

     (D) Install temporary supplies

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04. A single-phase double-wound transformer consists of

     (A) A single core mounted winding

     (B) A winding that carries the difference between IP and IS

     (C) A single solid core

     (D) Two electrically separated coils

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05. It is necessary to avoid skin contact with quartz lamps, as it

     (A) Reduces the life of the lamp

     (B) Could cause burns

     (C) Generates excessive heat

     (D) Lengthens lampworking life

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06. A parallel AC circuit in resonance will

     (A) Have a high voltage developed across each inductive and capacitive section

     (B) Have high impedance

     (C) Act like a resistor of low value

     (D) Have current in each section equal to the line current

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07. Which of the following waves has the highest value of peak factor?

     (A) Square wave

     (B) Sine wave

     (C) Half wave rectified sine wave

     (D) Triangular wave

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08. The equation of 50 Hz current sine wave having r.m.s. value of 60 A is

     (A) 60 sin 25 t

     (B) 60 sin 50 t

     (C) 84.84 sin 314 t

     (D) 42.42 sin 314 t

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09. If resistance is 20 Q and inductance is 27 in a R-L series circuit, then time constant of this circuit will be

     (A) 0.001 s

     (B) 0.1 s

     (C) 10 s

     (D) 100 s

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10. If two sine waves of the same frequency have a phase difference of JT radians, then

     (A) Both will reach their minimum values at the same instant

     (B) Both will reach their maximum values at the same instant

     (C) When one wave reaches its maximum value, the other will reach its minimum value

     (D) None of the above

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11. The electrostatic stress in underground cables is

     (A) Same at the conductor and the sheath

     (B) Minimum at the conductor and maximum at the sheath

     (C) Maximum at the conductor and minimum at the sheath

     (D) Zero at the conductor as well as on the sheath

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12. An ideal voltage source has

     (A) Zero internal resistance

     (B) Open circuit voltage equal to the voltage on full load

     (C) Terminal voltage in proportion to current

     (D) Terminal voltage in proportion to load

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13. Reduced voltage starter can be used with

     (A) Slip ring motor only but not with squirrel cage induction motor

     (B) Squirrel cage induction motor only but not with slip ring motor

     (C) Squirrel cage as well as slip ring induction motor

     (D) None of the above

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14. The steady state stability of the power system can be increased by

     (A) Connecting lines in parallel

     (B) Connecting lines in series

     (C) Using machines of high impedance

     (D) Reducing the excitation of machines

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15. To understand how the output voltage is shaped by a differentiator, you must consider

     (A) The response to the rising pulse edge

     (B) The response between the rising and falling edges

     (C) The response to the falling pulse edge

     (D) All of the above

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 Next Quiz Tests:

Set 01

Set 02

Set 03

Set 04

Set 05

Set 06

Set 07

Set 08

Set 09