electrical engineering Mcqs
1. economics of power generation2. analog electronics3. solid state switching circuits4. parallel circuits5. switchgear and protection6. op amp circuits7. transistor audio power amplifiers8. electrostatics9. heating and welding10. multi stage transistor amplifiers11. passive filters12. network theorems13. regulated d c power supply14. a c fundamentals circuits and circuit theory15. electromagnetic induction16. power electronics17. magnetism and electromagnetism18. transformers19. modulation and demodulation20. d c generators21. semiconductor theory22. single phase induction motors23. semiconductor diode24. hybrid parameters25. digital electronics26. oscillators27. earthing or grounding28. single stage transistor amplifiers29. d c motors30. transistor biasing31. amplifiers with negative feedback32. basic electrical33. electronic instruments34. synchronous motors35. field effect transistors fet36. magnetic circuit37. control systems38. industrial drives39. power generation40. series parallel circuits41. transistor tuned amplifiers42. electrical engineering materials43. rectifiers and converters44. integrated circuits45. scr silicon controlled rectifiers46. cables47. polyphase induction motors48. measurement and instrumentation49. transistors50. electrical machine design51. electrolysis and storage of batteries52. electric traction53. transmission and distribution
1751. Ageing of a selenium rectifier may change the output voltage by__________?
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A. none of the above

B. 5 to 10 per cent

C. 15 to 20 per cent

D. 25 to 30 per cent

1752. A dielectric material must be____________?
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A. good conductor

B. semi conductor

C. insulator

D. resistor

1753. The efficiency of an electrolytic rectifier is nearly____________?
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A. 70%

B. 60%

C. 80%

D. 40%

1754. at a point is equal to the negative potential gradient at that point?
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A. Electric flux

B. Magnetic flux density

C. Magnetic flux

D. Electric intensity
1755. The co-efficient of coupling between two air core coils depends on____________?
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A. none of the above

B. mutual inductance between two coils only

C. self-inductance of two coils only

D. mutual inductance and self inductance of two coils
1756. Mica capacitors are characterized by all of the following except___________?
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A. accurate value

B. low leakage reactance

C. low losses

D. stable operation

1757. The value of dielectric constant for vacuum is taken as____________?
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A. 10

B. 1

C. zero

D. 4

1758. The time constant and R-C circuit may also be defined as the time during which the charging current falls to ________ percent of its initial maximum value
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A. 42

B. 63

C. 37

D. 73

1759. Paper capacitors usually have a tolerance of___________?
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A. 10%

B. 15%

C. 20%

D. 5%

1760. Cells are connected in parallel to__________?
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A. increase the voltage output

B. increase the current capacity

C. increase the internal resistance

D. increase the efficiency

1761. Petroleum jelly is applied to the electrical connections to the lead-acid battery___________?
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A. reduce path resistance

B. prevent short-circuiting

C. prevent local heating

D. prevent corrosion
1762. The bridge used for the measurement of the value of the capacitance is____________?
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A. Wheatstone bridge

B. Wiens bridge

C. Schering bridge

D. Hays bridge

1763. A mica capacitor and a ceramic capacitor both have the same physical dimensions. Which will have more value of capacitance _______?
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A. Ceramic capacitor

B. Mica capacitor

C. Both will have identical value of capacitance

D. It depends on applied voltage

1764. In order to remove static electricity from machinery___________?
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A. humidify the surroundings

B. construct insulated cabins

C. insulate the machinery

D. ground the framework
1765. A typical output of a solar cell is_____________?
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A. 0.1V

B. 0.26 V

C. 2 V

D. 1.1 V

1766. The efficiency of the copper oxide rectifier seldom exceeds____________?
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A. 65 to 75%

B. 80 to 85%

C. 85 to 90%

D. 90 to 95%

1767. The law that the induced e.m.f. and current always oppose the cause producing them is due to____________?
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A. Lenz

B. Newton

C. Coulomb

D. Faraday

1768. In a capacitive circuit___________?
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A. none of the above

B. a steady value of applied voltage causes discharge

C. an increase in applied voltage makes a capacitor charge

D. decrease in applied voltage makes a capacitor charge

1769. A material for good magnetic memory should have____________?
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A. high retentivity

B. low retentivity

C. high permeability

D. low hysteresis loss

1770. It is the_________of the transformer on which the magnitude of angle of overlap depends?
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A. any of the above

B. leakage reactance

C. resistance

D. capacitance

1771. If A.C. voltage is applied to capacitive circuit, the alternating current can flow in the circuit because__________________?
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A. varying voltage produces the charging and dicharging currents

B. charging current can flow

C. of high peak value

D. discharge current can flow

1772. The surface integral of the normal component of the electric displacement D over any closed surface equals the charge enclosed by the surface. The above statement is associated with_______?
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A. Gausss law

B. Lenzs law

C. Kirchhoff s law

D. Faradays law

1773. Permittivity is expressed in_____________?
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A. Farad/sq-m

B. Weber/sq-m

C. Weber/meter

D. Farad/meter
1774. What is the value of capacitance that must be connected in parallel with 50 pF condenser to make an equivalent capacitance of 150 pF ?
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A. 200 pF

B. 150 pF

C. 100 pF

D. 50 pF

1775. Which of the fpllowing inductor will have the least eddy current losses ?
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A. Air core

B. Laminated iron core

C. Powdered iron core

D. Iron core

1776. In case all the flux from the current in coil 1 links with coil 2, the co-efficient of coupling will be____________?
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A. 1.0

B. zero

C. 0.5

D. 2

1777. Dielectric strength of mica is___________?
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A. 300 to 500 kV/mm

B. 30 to 50 kV/mm

C. 50 to 200 kV/mm

D. 10 to 20 kV/mm

1778. An electrolytic capacitor is generally made to provide__________?
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A. fixed capacitance

B. low capacitance

C. large value of capacitance

D. variable capacitance

1779. If three 15 uF capacitors are connected in series, the net capacitance is
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A. 30 uF

B. 5 uF

C. 45 uF

D. 50 uF

1780. Out of the following capacitors of identical rating which one will have the smallest dimensions ___________ ?
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A. Ceramic capacitor

B. Mica capacitor

C. Paper capacitor

D. Aluminium foil capacitor

1781. Find the force acting on a conductor 3m long carrying a current of 50 amperes at right angles to a magnetic field having a flux density of 0.67 tesla
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A. 1000 N

B. 400 N

C. 600 N

D. 100 N
1782. A laminated iron core has reduced eddy-current losses because____________?
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A. the laminations are stacked vertfcally

B. the laminations are insulated from each other

C. the magnetic flux is concentrated in the air gap of the core

D. more wire can be used with less D.C. resistance in coil

1783. Which of the following is unit of inductance ?
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A. Webers/metre

B. Henry

C. Ampere turns

D. Ohm

1784. Electric intensity at any point in an electric field is equal to the at that point?
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A. potential gradient

B. none of the above

C. electric flux

D. magnetic flux density

1785. When both the inductance and resistance of a coil are doubled the value of________________?
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A. initial rate of rise of current is doubled

B. time constant remains unchanged

C. final steady current is doubled

D. time constant is halved

1786. The capacitance C is charged through a resistance R. The time constant of the charging circuit is given by__________?
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A. RIC

B. CIR

C. 1/RC

D. RC
1787. The units of capacitance are____________?
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A. coulombs/volt

B. ohms

C. volts/coulomb

D. henry/Wb

1788. A 500 turns solenoid develops an average induced voltage of 60 V. Over what time interval must a flux change of 0.06 Wb occur to produce such a voltage ?
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A. 5 s

B. 0.5 s

C. 0.01 s

D. 0.1 s

1789. The metal rectifiers are preferred to valve rectifiers due to which of the following advantages ?
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A. They are mechanically strong

B. They do not require any voltage for filament heating

C. Both (A) and (B)

D. None of the above

1790. The time constant of an R-C circuit is defined as the time during which capacitor charging voltage actually rises to _________ percent of its value
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A. 37, final

B. 62, final

C. 62, initial

D. 37, initial

1791. Energy stored by a coil is doubled when its current is increased by percent___________?
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A. 50

B. 100

C. 25

D. 41.4
1792. When 4 volts e.m.f. is applied across a 1 farad capacitor, it will store energy of_____________?
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A. 4 joules

B. 8 joules

C. 6 joules

D. 2 joules

1793. Which of the following statements is incorrect ?
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A. A capacitor can store charge because it has a dielectric between two conductors

B. The thinner the dielectric, the more the capacitance and the lower the voltage breakdown rating for a capacitor .

C. A six dot mica capacitor colour coded white, green, black, red and yellow has the capacitance value of 500 pF

D. Capacitors in series provide less capacitance but a higher voltage breakdown rating for the combination

1794. Silicon steel is used in electrical machines because it has_____________?
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A. low coercivity

B. low hysteresis loss

C. high coercivity

D. low retentivity

1795. Which of the following rectifiers have been used extensively in supplying direct current for electroplating ?
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A. Selenium rectifiers

B. Mechanical rectifiers

C. Copper oxide rectifiers

D. Mercury arc rectifiers

E. None of the above

1796. Which of the following factors adversely affects the capacity of the leadacid battery ?
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A. Rate of discharge

B. All of the above

C. Temperature of surroundings

D. Specific gravity of electrolyte

1797. Which of the following battery is used for air-craft _____________?
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A. Dry cell battery

B. Lead-acid battery

C. Silver oxide battery

D. Nickel-iron battery
1798. Dielectric strength of a material depends on_____________?
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A. moisture content

B. temperature

C. thickness

D. all of the above

E. none of the above

1799. The electric field at a point situated at a distance d from straight charged conductor is____________?
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A. none of the above

B. inversely proportional to d

C. proportional to d

D. inversely proportional to d
1800. Which of the following has lower specific gravity V__________?
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A. Any of the above

B. Dilute H2S04

C. Concentrated H2SO4

D. Water