Bel electronics and electrical question papers
Bel Electrical Engineering Objective Questions
1. Capacitive reactance for singlephase series a.c circuit is
2. Which one of the following test used for testing dc machines
a) Shortcircuit test
b) Back to Back test
c) Brake Test
d) All of the above
3. If transformer secondary is open, which draw some current is known as
a) Secondary current
b) noload primary current
c) noload secondary current
d) None of the above
4. If the generator bearings is hot the reason is
a) eddy current
b) Operation at low speed
c) Less oil
d) None of the above
5. Which one of the following is ptype impurities
a) Phosphorus
b) Aluminium
c) Antimony
d) None of the above
6.Which one of the following is a parts of centrifugal pump
a) Draft tube
b) Breaking jet
c) Impeller
d) All of the above
7. Chopper used to convert
a) Constant dc voltage in to variable dc voltage
b) DC power in to AC power
c) AC power in to DC power
d) None of the above
8. What are the input, output terminal of a transistor in common base circuit configuration
a) Base Input, Collector Output
b) Emitter Input, Collector Output
c) Collector Input, Emitter Output
d) None of the above
9. Common collector amplifier is also called
a) Emitter Follower
b) Register
c) Voltage Regulator
d) None of the above
10. Silicon controlled switch is a
a) 4 terminal PNPN device
b) 4 layer PNPN device
c) 3 layer, 3 terminal PNPN device
d) a & b are correct
11. A tunnel diode is used for
a) Pulse generator
b) Square wave generator
c) Microwave frequencies
d) None of the above
12. Density of fluid is defined as the ratio of
13. Which one of the following device used to measure pressure of a fluid
a) Venturimeter
b) Orifice meter
c) Manometers
d) pitot tube
14. Hydraulic machines which converts
a) hydraulic in to mechanical energy
b) Mechanical energy in to hydraulic energy
c) Mechanical energy in to electrical energy
d) None of the above
15. Apply Kirchoff's current law to below circuit
16. Shuntwound Generators (selfexcited) used for
a) Boosters
b) Charging Batteries
c) a & b are correct
d) None of the above.
17. If a generator gives spark on commutator the reason is
a) Overload
b) Armature Shortcircuit
c) a & b are correct
d) None of the above
18 The equipment required for protection of transformers.
a) Breather
b) Conservator
c) Emergency release
d) Temperature Gauge
e) All of the above
19. Why flux is used for soldering?
a) To remove oxides from the surface to be soldered
b) it is used as a paste
c) without flux cannot solder
d) None of the above
20. Empire cloth is used for
a) Overhead lines
b) switches
c) Insulating the machines while winding
d) None of the above
21. Thermal efficiency is defined as the ratio of
a) Output Energy / Input Energy
b) (Output Energy / Input Energy) x 100
c) Useful heat / Total heat
d) (Useful heat / Total heat) x 100
22. Moving iron attraction type meter used for
a) Measure current in A.C
b) Measure current in D.C
c) a & b are correct
d) None of the above
23. Moving coil instrument used in
a) ac only
b) dc only
c) both ac & dc
d) None of the above
24. Fluorescent lamp circuit is a
a) Series Circuit
b) Parallel Circuit
c) Combination of series & Parallel Circuit
d) None of the above
25. In Fluorescent lamp circuit why choke is used
a) it gives low Voltage impulse for starting lamp
b) It gives high Voltage impulse for starting lamp
c) It prevent the lamp from overvoltages
d) it acts as a stabillizer
26. Alternators are rated in
a) KW b) KVA
c) KVAR
d) None of the above
27. The inverse of reluctance is called
a) Permence
b) Permittance
c) Saturation
d) None of the above
28 . Ci rcul ati ng current protecti on scheme used i n
a) busbar Answer
b) Transformer
c) Feeder
d) None of the above
29. Ti me -graded protecti on scheme used i n
a) busbar
b) Transformer
c) Feeder Answer
d) Transmi ssi on l i ne
30. Carri er current protecti on scheme used i n
a) Busbar
b) Transformer
c) Feeder Answer
d) Reactor
31. FET i s a
a) Bi pol ar devi ce
b) Uni pol ar devi ceAnswer
c) Curent Control l ed devi ce
d) None of the above
32. BJT i s a
a) Uni pol ar devi ce
b) Vol tage control l ed devi ce-
c) Bi pol ar devi ce -Answer
d) None of the above
33. Current carri er hol es are el ectrons for
a) N Channel JFET -Answer
b) P Channel JFET
c) a & b are correct
d) None of the above
34. I n Enhancement mode the MOSFET operates when
a) Gate vol tage i s negati ve
b) Drai n vol tage i s negati ve
c) Source Vol tage i s posi ti ve
d) Gate vol tage i s posi ti ve-Answer
35. MOSFET operates i n
a) onl y i n enhancement method
b) onl y i n depl eti on method
c) a and b are correct-Answer
d) None of the above
36. Power MOSFET i s a
a) Current control l ed devi ce
b) Vol tage control l ed devi ce-Answer
c) a & b are correct
d) none of the above
37. FET i s a
a) Bi pol ar devi ce
b) Current control l ed devi ce-Answer
c)Three termi nal semi conductor devi ce
d) none of the above
38 . Zener di ode i s a
a) Vol tage regul ator di ode
b) Breakdown di ode
c) Current regul ator di ode-Answer
d) a and b are correct
39. Epi taxi al growth method used i n
a) I C Fabri cati on -Answer
b) MOSFET Fabri cati on
c) BJT Fabri cati on
d) None of the above
40Di stance Rel ays operates when
a) The rati o V/I i s l ess than a predetermi ned val ue-Answer
b) The rati o V/I i s hi gher than a predetermi ned
c) a and b are correct
d) None of the above
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