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
4951. The use of permanent magnets is. not made in_____________?
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A. energy meters

B. loud-speakers

C. transformers

D. magnetoes

4952. The uniform magnetic field is______________?
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A. the field in which all lines of magnetic flux are parallel and equidistant

B. the field of a set of parallel conductors

C. none of the above

D. the field of a single conductor

4953. The unit of relative permeability is_____________?
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A. it is dimensionless

B. henry/sq. m

C. henry/metre

D. henry

4954. Which of the following is expected to have the maximum permeability ?
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A. Ebonite

B. Copper

C. Brass

D. Zinc

4955. Which of the following statements is correct ?
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A. The magnetic flux inside the exciting coil is same as on its outside surface

B. The magnetic flux inside an exciting coil is zero

C. The magnetic flux inside an exciting coil is lower than its outside surface

D. The magnetic flux inside the exciting coil is greater than its outside surface

4956. Which of the following materials are diamagnetic ?
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A. Silver

B. Copper

C. Iron

D. Silver and copper
4957. The force between two long parallel conductors is inversely proportional to_____________?
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A. radius of conductors

B. current in one conductor

C. distance between the conductors

D. product of current in two conductors

4958. One maxwell is equal to____________?
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A. 10 webers

B. 10 webers

C. 10 webers

D. 10 webers

4959. he retentivity (a property) of material is useful for the construction of_______________?
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A. electromagnets

B. permanent magnets

C. non-magnetic substances

D. transformers

4960. The magnetic reluctance of a material______________?
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A. decreases with increasing cross sectional area of material

B. does not vary with increasing cross-sectional area of material

C. any of the above

D. increases with increasing cross-sec-tional area of material

4961. A 300 mm long conductor is carrying a current of 10 A and is situated at right angles to a magnetic field having a flux density of 0.8 T ; the force on the conductor will be____________?
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A. 240 N

B. 0.24 N

C. 2.4 N

D. 24 N

4962. Which of the following is a ferromagnetic material ?
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A. Tungsten

B. Copper

C. Aluminium

D. Nickel
4963. The susceptibility of paramagnetic materials generally lies between____________?
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A. 1CT3 and 1CT7

B. 10?2 and KT5

C. KT4 and KT8

D. KT3 and 1CT6
4964. Ferrites are a sub-group of_______________?
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A. ferro-magnetic materials

B. paramagnetic materials

C. ferri-magnetic materials

D. non-magnetic materials

4965. The unit of flux is the same as that of_______________?
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A. resistance

B. reluctance

C. pole strength

D. permeance

4966. Flemings left hand rule is used to find_________________?
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A. direction of flux in a solenoid

B. direction of magnetic field due to current carrying conductor

C. polarity of a magnetic pole

D. direction of force on a current carrying conductor in a magnetic field
4967. Main causes of noisy solenoid are______________?
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A. strong tendency of fan out of laminations at the end caused by repulsion among magnetic lines of force

B. uneven bearing surface, caused by dirt or uneven wear between moving and stationary parts

C. both of above

D. none of the above

4968. When a magnet is in motion relative to a coil the induced e.m.f. does not depend upon____________?
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A. number of turns of the coil

B. motion of the magnet

C. resistance of the coil

D. pole strength of the magnet

4969. Hysteresis loop in case of magnetically hard materials is more in shape as compared to magnetically soft materials
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A. triangular

B. circular

C. rectangular

D. none of the above

4970. What will be the magnetic potential difference across the air gap of 2 cm length in magnetic field of 200 AT/m ?
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A. 6 AT

B. 4 AT

C. 2 AT

D. 10 AT

4971. Paramagnetic materials have relative permeability________________?
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A. equal to unity

B. slightly more than unity

C. slightly less than unity

D. equal to that ferromagnetic mate rials

4972. For which of the following materials the net magnetic moment should be zero ?
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A. Ferrimagnetic materials

B. Diamagnetic materials

C. Antiferromagnetic materials

D. Antiferrimagnetic materials

4973. A transformer core is laminated to__________?
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A. reduce copper losses

B. reduce hysteresis loss

C. reduce eddy current losses

D. reduce all above losses

4974. The no load current in a transformer lags behind the applied voltage by an angle of about_____________?
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A. 90

B. 120?

C. 75

D. 180

4975. Which type of winding is used in 3 phase shell-type transformer?
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A. Circular type

B. Sandwich type

C. Rectangular type

D. Cylindrical type

4976. No-load current of a transformer has_____________?
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A. has small magnitude and low power factor

B. has small magnitude and high power factor

C. has high magnitude and high power factor

D. has high magnitude and low power factor

4977. Spacers are provided between adjacent coils?
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A. to provide free passage to the cooling oil

B. to insulate the coils from each other

C. both A. and (b)

D. none of the above

4978. A common method of cooling a power transformer is_______________?
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A. any of the above

B. natural air cooling

C. oil cooling

D. air blast cooling

4979. The noise resulting from vibrations of laminations set by magnetic forces, is termed as_________________?
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A. zoom

B. magnetostrication

C. hum

D. boo

4980. Delta/star transformer works satisfactorily when______________?
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A. on balanced as well as unbalanced loads

B. none of the above

C. load is balanced only

D. load is unbalanced only

4981. The path of a magnetic flux in a transformer should have______________?
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A. high reluctance

B. low resistance

C. high resistance

D. low reluctance
4982. The full-load copper loss of a transformer is 1600 W. At half-load, the copper loss will be___________?
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A. 1600 W

B. 800 W

C. 6400 W

D. 400 W
4983. Iron loss of a transformer can be measured by____________?
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A. any type of wattmeter

B. frequency meter

C. low power factor wattmeter

D. unity power factor wattmeter

4984. Which winding of the transformer has less cross-sectional area?
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A. Low voltage winding

B. Primary winding

C. Secondary winding

D. High voltage winding
4985. Which of the following property is not necessarily desirable in the material for transformer core ?
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A. Low hysteresis loss

B. Mechanical strength

C. High permeability

D. High thermal conductivity
4986. The magnetising current of a transformer is usually small because it has___________?
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A. laminated silicon steel core

B. small air gap

C. large leakage flux

D. fewer rotating parts

4987. In a transformer the resistance between its primary and secondary should be_____________?
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A. 1000 Q

B. infinity

C. zero

D. 10 Q

4988. Harmonics in transformer result in___________?
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A. increased I2R losses

B. increased core losses

C. all of the above

D. magnetic interference with communication circuits

4989. Which of the following parts of a transformer is visible from outside ?
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A. Primary winding

B. Bushings

C. Core

D. Secondary winding

4990. In a step-down transformer, there is a change of 15 A in the load current. This results in change of supply current of_________________?
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A. more than 15 A

B. none of the above

C. less than 15 A

D. 15 A

4991. Losses which occur in rotating electric machines and do not occur in transformers are___________?
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A. hysteresis and eddy current losses

B. friction and windage losses

C. copper losses

D. magnetic losses

4992. The power transformer is a constant______________?
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A. voltage device

B. power device

C. main flux device

D. current device

4993. Natural oil cooling is used for transformers up to a rating of____________?
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A. 1000 kVA

B. 250 kVA

C. 3000 kVA

D. 500 kVA

4994. A good voltage regulation of a transformer means________________?
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A. output voltage fluctuation from no load to full load is least

B. ood voltage regulation of a transformer means

C. difference between primary and secondary voltage is maximum

D. output voltage fluctuation with power factor is least

E. difference between primary and secondary voltage is least

4995. The function of conservator in a transformer is___________________?
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A. to cool the transformer oil

B. to take care of the expansion and contraction of transformer oil due to variation of temperature of sur-roundings

C. to project againstinternal fault

D. to reduce copper as well as core losses

4996. Power transformers are generally designed to have maximum efficiency around__________?
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A. half-load

B. 10% overload

C. near full-load

D. no-load

4997. In a given transformer for given applied voltage, losses which remain constant irrespective of load changes are______________?
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A. none of the above

B. copper losses

C. hysteresis and eddy current losses

D. friction and windage losses

4998. In a power or distribution transformer about 10 per cent end turns are heavily insulated__________?
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A. to withstand the high voltage drop due to line surge produced by the shunting capacitance of the end turns

B. none of the above

C. to reflect the line surge and save the winding of a transformer from damage

D. to absorb the line surge voltage and save the winding of transformer from damage

4999. During open circuit test of a transformer:
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A. primary is supplied rated kVA

B. primary is supplied rated voltage

C. primary is supplied current at reduced voltage

D. primary is supplied full-load current

5000. The path of the magnetic flux in transformer should have____________?
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A. high reluctance

B. high resistance

C. low reactance

D. low resistance