BSNL MT

TELECOM OPERATIONS

1. Materials and Components

2. Physical Electronics, Electron Devices and ICs

3. Signals and Systems

4. Network theory

5. Electromagnetic Theory

6.Electronic Measurements and Instrumentation

7. Analog Electronic Circuits

8. Digital Electronic Circuits

9. Control Systems

10. Communication Systems

11. Microwave Engineering

12. Computer Engineering

13. Power Electronics

1.The S.I. unit of power is (a) henry (b) coulomb (c) watt (d) watt-hour Ans: c 2. Electric pressure is also called (a) resistance (b) power (c) voltage (d) energy Ans: c 3.The substances which have a large number of free electrons and offer a low resistance are called (a) insulators (b) inductors (c)semi-conductors (d)conductors Ans: d 4.Out of the following which is not a poor conductor ? (a) Cast iron (b) Copper (c) Carbon (d) Tungsten Ans: b 5.Out of the following which is an insulating material ? (a) Copper (b) Gold (c) Silver (d) Paper Ans: d 1. Laminations of core are generally made of (a) case iron (b) carbon (c)silicon steel (d)stainless steel Ans: c 2. Which of the following could be lamina-proximately the thickness of lamina-tions of a D.C. machine ? (a)0.005 mm (b)0.05 mm (c)0.5 m (d)5 m Ans: c 3. The armature of D.C. generator is laminated to (a) reduce the bulk (b) provide the bulk (c)insulate the core (d)reduce eddy current loss Ans: d 4.The resistance of armature winding depends on (a) length of conductor (b) cross-sectional area of the conductor (c)number of conductors (d)all of the above Ans: d 5.The field coils of D.C. generator are usually made of (a) mica (b) copper (c) cast iron (d) carbon Ans: b

1.The property of coil by which a counter e.m.f. is induced in it when the current through the coil changes is known as (a) self-inductance (b) mutual inductance (c) series aiding inductance (d) capacitance Ans: a 2.As per Faraday's laws of electromagnetic induction, an e.m.f. is induced in a conductor whenever it (a) lies perpendicular to the magnetic flux (b) lies in a magnetic field (e) cuts magnetic flux (d) moves parallel to the direction of the magnetic field Ans: c 3.Which of the following circuit element stores energy in the electromagnetic field ? (a) Inductance (b) Condenser (c) Variable resistor (d) Resistance Ans: a 4.The inductance of a coil will increase under all the following conditions except (a) when more length for the same number of turns is provided (6) when the number of turns of the coil increase (c) when more area for each turn is provided (d) when permeability of the core increases Ans: a 5. Higher the self-inductance of a coil, (a) lesser its weber-turns (b) lower the e.m.f. induced (c) greater the flux produced by it (d) longer the delay in establishing steady current through it Ans: d 1.A sine wave has a frequency of 50 Hz. Its angular frequency is _______ radian/second. (a) 100 n (b) 50 jt (c) 25 jt (d) 5 n Ans: a 2.The reactance offered by a capacitor to alternating current of frequency 50 Hz is 20 Q. If frequency is increased to 100 Hz, reactance becomes_____ohms. (a) 2.5 (b) 5 (c) 10 (d) 15 Ans: c 3.The period of a wave is (a) the same as frequency (b) time required to complete one cycle (c)expressed in amperes (d)none of the above Ans: b

4.The form factor is the ratio of (a) peak value to r.m.s. value (b) r.m.s. value to average value (c)average value to r.m.s. value (d)none of the above Ans: b 5.The period of a sine wave is _____ seconds. Its frequency is (a) 20 Hz (b) 30 Hz (c) 40 Hz (d) 50 Hz Ans: d 1. The insulating material for a cable should have (a) low cost (b) high dielectric strength (c) high mechanical strength (d) all of the above Ans: d 2. Which of the following protects a cable against mechanical injury ? (a) Bedding (b) Sheath (c) Armouring (d) None of the above Ans: c 3. Which of the following insulation is used in cables ? (a) Varnished cambric (b) Rubber (c) Paper (d) Any of the above Ans: d 4. Empire tape is (a) varnished cambric (b) vulcanised rubber (c) impregnated paper (d) none of the above Ans: a 5. The thickness of the layer of insulation on the conductor, in cables, depends upon (a) reactive power (b) power factor (c) voltage (d) current carrying capacity Ans: c 1. In an open loop control system (a) Output is independent of control input (b) Output is dependent on control input (c) Only system parameters have effect on the control output (d) None of the above Ans: a

2. For open control system which of the following statements is incorrect ? (a) Less expensive (b) Recalibration is not required for maintaining the required quality of the output (c) Construction is simple and maintenance easy (d) Errors are caused by disturbances Ans: b 3. A control system in which the control action is somehw dependent on the output is known as (a) Closed loop system (b)Semiclosed loop system (c)Open system (d)None of the above Ans: a 4. In closed loop control system, with positive value of feedback gain the overall gain of the system will (a) decrease (b) increase (c) be unaffected (d) any of the above Ans: a 5. Which of the following is an open loop control system ? (a) Field controlled D.C. motor (b) Ward leonard control (c)Metadyne (d)Stroboscope Ans: a 1.The property of coil by which a counter e.m.f. is induced in it when the current through the coil changes is known as (a) self-inductance (b) mutual inductance (c) series aiding inductance (d) capacitance Ans: a 2.As per Faraday's laws of electromagnetic induction, an e.m.f. is induced in a conductor whenever it (a) lies perpendicular to the magnetic flux (b) lies in a magnetic field (e) cuts magnetic flux (d) moves parallel to the direction of the magnetic field Ans: c 3.Which of the following circuit element stores energy in the electromagnetic field ? (a) Inductance (b) Condenser (c) Variable resistor (d) Resistance Ans: a 4.The inductance of a coil will increase under all the following conditions except (a) when more length for the same number of turns is provided (6) when the number of turns of the coil increase (c) when more area for each turn is provided (d) when permeability of the core increases Ans: a 5. Higher the self-inductance of a coil, (a) lesser its weber-turns (b) lower the e.m.f. induced (c) greater the flux produced by it (d) longer the delay in establishing steady current.

Ans: d 1. The converse of hardness is known as (a) malleability (b) toughness (c) softness (d) none of the above Ans: c 2. On which of the following factors does the resistivity of a material depend ? (a)Resistance of the conductor (b)Area of the conductor section (c)Length of the conductor (d) All of the above Ans: d 3. Is a negatively charged particle present in an atom. (a) Proton (b)Neutron (c)Electron (d) None of the above Ans: c 4. The formula ____ determines the number of electrons that can be accommodated in any level. (a) 2n2 (b)4n2 (c)2n3 (d)4ns Ans: a 5. The tiny block formed by the arrangement of a small group of atoms is called the (a) unit cell (b)space lattice (c)either (a) or (b) (d) none of the above Ans: a 1."The mass of an ion liberated at an electrode is directly proportional to the quantity of electricity". The above statement is associated with (a)Newton's law (b)Faraday's law of electromagnetic (c)Faraday's law of electrolysis (d)Gauss's law Ans: c 2.The charge required to liberate one gram equivalent of any substance is known as ______ constant (a) Time b) Faraday's (c) Boltzman Ans: b 3.During the charging of a lead-acid cell (a) its voltage increases (b) it gives out energy (c) its cathode becomes dark chocolate brown in colour (d) specific gravity of H2SO4 decreases Ans: a

4.The capacity of a lead-acid cell does not depend on its (a) temperature (b) rate of charge (c) rate of discharge (d) quantity of active material Ans: b 5.During charging the specific gravity of the electrolyte of a lead-acid battery (a) increases (b) decreases (c) remains the same (d) becomes zero Ans: a 1. The force between two charges is 120 N. If the distance between the charges is doubled, the force will be (a) 60 N (b) 30 N (c) 40 N (d) 15 N Ans: b 2. The electric field intensity at a point situated 4 metres from a point charge is 200 N/C. If the distance is reduced to 2 metres, the field intensity will be (a) 400 N/C (b) 600 N/C (c) 800 N/C (d) 1200 N/C Ans: c 3. The lines of force due to charged particles are (a) always straight (b) always curved (c) sometimes curved (d) none of the above Ans: b 4. The electric field at a point situated at a distance d from straight charged conductor is (a) proportional to d (b) inversely proportional to d (c) inversely proportional to d (d) none of the above Ans: b 5. The direction of electric field due +0 positive charge is . (a) away from the charge (b) towards the charge (c) both (a) and (6) (d) none of the above Ans: a

6. A field line and an equipotential surface are (a) always parallel (b) always at 90° (c) inclined at any angle 0 (d) none of the above Ans: b 7. The ability of charged bodies to exert force on 6ne another is attributed to the existence

of

(a) electrons

(b) protons

(c) neutrons

(d) electric field

Ans: d

8. If the sheet of a bakelite is inserted between the plates of an air capacitor, the capacitance

will

(a) decrease

(b) increase

(c) remains unchanged

(d) become zero

Ans: b

9. A capacitor stores 0.24 coulombs at 10 volts. Its capacitance is

(a) 0.024 F

(b) 0.12 F

(c) 0.6 F

(d) 0.8 F

Ans: a

10. For making a capacitor, it is better to select a dielectric having

(a) low permittivity

(b) high permittivity

(c) permittivity same as that of air

(d) permittivity slightly more than that of air

Ans: b

11. The units of capacitance are

(a) volts/coulomb

(b) coulombs/volt

(c) ohms

(d) henry/Wb

Ans: b

12. If three 15 uF capacitors are connected in series, the net capacitance is

(a) 5 uF

(6) 30 uF

(c) 45 uF

(d) 50 uF

Ans: a

13. If three 10 uF capacitors are connected in parallel, the net cararitanceis

(a) 20 uF

(b) 30 uE

(c) 40 uF

(d) 50 uF

Ans: b

14. A dielectric material must be

(a) resistor

(b) insulator

(c) good conductor

(d) semi conductor

Ans: b

15. An electrolytic capacitor can be used for

(a) D.C. only

(b) AC. only

(c) both D.C. as well as A.C.

Ans: a

16. The capacitance of a capacitor is not affected by

(a) distance between plates

(6) area of plates

(c) thickness of plates

(d) all of the above

Ans: c

17. Which of the following is not a vector ?

(a) Linear momentum

(b) Angular momentum

(c) Electric field

(d) Electric potential

Ans: b

18. Two plates of a parallel plate capacitor after being charged from a constant voltage source

are separated apart by means of insulated handles, then the

(a) Voltage across the plates increases

(b) voltage across the plates decreases

(c) charge on the capacitor decreases

(d) charge on the capacitor increases

Ans: b

19. If A.C. voltage is applied to capacitive circuit, the alternating current can flow in the circuit

because

(a) varying voltage produces the charg¬ing and dicharging currents

(b) of high peak value

(c) charging current can flow

(d) discharge current can flow

Ans: a

20. Voltage applied across a ceramic dielectric produces an electrolytic field 100 times greater

than air. What will be the value of dielectric constant ?

(a) 50

(6) 100

(c) 150

(d) 200

Ans: b

21. Which of the following statements is correct ?

(a) Air capacitors have a blackband to indicate the outside foil

(6) Electrolytic capacitor must be con¬nected in the correct polarity

(c) Ceramic capacitors must be con¬nected in the correct polarity

(d) Mica capacitors are available in capacitance value of 1 to 10 pF

Ans: b

22. The dissipation factor of a good dielectric is of the order of

(a) 0.0002

(b) 0.002

(c) 0.02

(d) 0.2

Ans: a

23. "The total electric flux through any closed surface surrounding charges is equal to the

amount oflcharge enclosed".

The above statement is associated with

(a) Coulomb's square law

(b) Gauss's law

(c) Maxwell's first law

(d) Maxwell's second law

Ans: b

24. Three capacitors each of the capacity C are given. The resultant capacity 2/3 C

can be obtained by using them

(a) all in series

(b) all in parallel

(c) two in parallel and third in series with this combination

(d) two in series and third in parallel across this combination

Ans: c

25. For which of the following parameter variation, the capacitance of the capacitor remains

unaffected ?

(a) Distance between plates

(b) Area of the plates

(c) Nature of dielectric

(d) Thickness of the plates

Ans: d

26. Which of the following statement is true ?

(a) The current in the discharging capacitor grows linearly

(b) The current in the dicharging capacitor grows exponentially

(c) The current in the discharging capacitor decays exponentially

(d) The current in the discharging capacitor decreases constantly

Ans: b

27. Which of the following expression is correct for electric field strength ?

(a) E = D/E

(b) E = D2/t

(c) E = jtD

(d) E= nD2

Ans: a

28. In a capacitor the electric charge is stored in

(a) metal plates

(b) dielectric

(c) both (a) and (6)

(d) none of the above

Ans: b

29. Which of the following materials has the highest value of dielectric constant?

(a) Glass

(b) Vacuum

(c) Ceramics

(d) Oil

Ans: c

30. Which of the following capacitors will have the least variation ?

(a) Paper capacitor

(b) Ceramic capacitor

(c) Silver plated mica capacitor

(d) None of the above

Ans: c

1. Which of the following is an advantage of heating by electricity ? (a) Quicker operation (b) Higher efficiency (c) Absence of flue gases (d) All of the above Ans: d 2. ________ has the highest value of thermal conductivity.

(a) Copper (b) Aluminium (c) Brass (d) Steel Ans: a 3. Which of the following heating methods has maximum power factor ? (a) Arc heating (b) Dielectric heating (c) Induction heating (d) Resistance heating Ans: d 4 method has leading power factor (a) Resistance heating (b) Dielectric heating (c) Arc heating (d) Induction heating Ans: b 5 is used for heating non-conducting materials. (a) Eddy current heating (b) Arc heating (c) Induction heating (d) Dielectric heating Ans: d

1. An air gap is usually inserted in magnetic circuits to (a) increase m.m.f. (b) increase the flux (c) prevent saturation (d) none of the above Ans: c 2. The relative permeability of a ferromagnetic material is (a) less than one (b) more than one (c) more than 10 (d) more than 100 or 1000 Ans: d 3. The unit of magnetic flux is (a) henry (b) weber (c) ampereturn/weber (d) ampere/metre Ans: b 4. Permeability in a magnetic circuit corresponds to______ in an electric circuit. (a) resistance (b) resistivity (c) conductivity (d) conductance Ans: c 5. Point out the wrong statement. Magnetic leakage is undesirable in electric machines because it (a) lowers their power efficiency (b) increases their cost of manufacture (c) leads to their increased weight (d) produces fringing Ans: a 1. Kirchhoff s current law states that (a) net current flow at the junction is positive (b) Hebraic sum of the currents meeting at the junction is zero (c) no curreht can leave the junction without some current entering it. (d) total sum of currents meeting at the junction is zero Ans: b 2. According to Kirchhoffs voltage law, the algebraic sum of all IR drops and e.m.fs. in any closed loop of a network is always (a) negative

(b) positive (c) determined by battery e.m.fs. (d) zero Ans: d 3. Kirchhoffs current law is applicable to only (a) junction in a network (b) closed loops in a network (c) electric circuits (d) electronic circuits Ans: a 4. Kirchhoffs voltage law is related to (a) junction currents (b) battery e.m.fs. (c) IR drops (d) both (b) and (c) (e) none of the above Ans: d 5. Superposition theorem can be applied only to circuits having (a) resistive elements (b) passive elements (c) non-linear elements (d) linear bilateral elements Ans: d 1.Which of the following component is usually fabricated out of silicon steel ? (a) Bearings (b) Shaft (c) Statorcore (d) None of the above Ans: c 2. The frame of an induction motor is usually made of (a) silicon steel (b) cast iron (c) aluminium (d) bronze Ans: b 3. The shaft of an induction motor is made of (a) stiff (b) flexible (c) hollow (d) any of the above Ans: a

4. The shaft of an induction motor is made of (a) high speed steel (b) stainless steel (c) carbon steel (d) cast iron Ans: c 5. In an induction motor, no-load the slip is generally (a) less than 1% (b) 1.5% (c) 2% (d) 4% Ans: a 1. By which of the following systems electric power may be transmitted ? (a) Overhead system (b) Underground system (c) Both (a) and (b) (d) None of the above Ans: c 2 are the conductors, which connect the consumer's terminals to the distribution (a) Distributors (b) Service mains (c) Feeders (d) None of the above Ans: b 3. The underground system cannot be operated above (a) 440 V (b) 11 kV (c) 33 kV (d) 66 kV Ans: d 4. Overhead system can be designed for operation upto (a) 11 kV (b) 33 kV (c) 66 kV (d) 400 kV Ans: c 5. If variable part of annual cost on account of interest and depreciation on the capital outlay is equal to the annual cost of electrical energy wasted in the conductors, the total annual cost will be minimum and the corresponding size of conductor will be most economical. This statement is known as (a) Kelvin's law (b) Ohm's law (c) Kirchhoffs law (d) Faraday's law (e) none of the above Ans: a

1) Resistivity of a wire depends on A. material B. length C. cross section area D. all of above 2) When n numbers resistances of each value r are connected in parallel, then the resultant resistance is x. When these n resistances are connected in series, total resistance is A. nx. B. n2x. C. x/n. D. rnx. 3) Resistance of a wire is r ohms. The wire is stretched to double its length, then its resistance will be A. r/2 B. 4r C. 2r D. r/4 4) Kirchhoff’s second law is based on law of conservation of A. charge B. energy C. momentum D. Mass 5) One coulomb of electrical charge is contributed by how many electrons ? A. 0.625 X 1019. B. 1.6 X 1019. C. 1019. D. 1.6 X 1012. 1.The number of digits in octal system is a.8 b.7 c.10 d. none 2..The number of digits in Hexadecimal system is a.15 b.17 c.16 d. 8 3.The number of bits in a nibble is a.16 b.5 c.4 d.8 4.The digit F in Hexadecimal system is equivalent to —— in decimal system a.16 b.15 c.17 d. 8 5.Which of the following binary numbers is equivalent to decimal 10 a.1000 b.1100 c.1010 d.1001 1. In an open loop control system (a) Output is independent of control input (b) Output is dependent on control input (c) Only system parameters have effect on the control output (d) None of the above Ans: a 2. For open control system which of the following statements is incorrect ? (a) Less expensive (b) Recalibration is not required for maintaining the required quality of the output

(c) Construction is simple and maintenance easy (d) Errors are caused by disturbances Ans: b 3. A control system in which the control action is somehw dependent on the output is known as (a) Closed loop system (b)Semiclosed loop system (c)Open system (d)None of the above Ans: a 4. In closed loop control system, with positive value of feedback gain the overall gain of the system will (a) decrease (b) increase (c) be unaffected (d) any of the above Ans: a 5. Which of the following is an open loop control system ? (a) Field controlled D.C. motor (b) Ward leonard control (c)Metadyne (d)Stroboscope Ans: a 1. The force between two charges is 120 N. If the distance between the charges is doubled, the force will be (a) 60 N (b) 30 N (c) 40 N (d) 15 N Ans: b 2. The electric field intensity at a point situated 4 metres from a point charge is 200 N/C. If the distance is reduced to 2 metres, the field intensity will be (a) 400 N/C (b) 600 N/C (c) 800 N/C (d) 1200 N/C Ans: c 3. The lines of force due to charged particles are (a) always straight (b) always curved (c) sometimes curved (d) none of the above Ans: b 4. The electric field at a point situated at a distance d from straight charged conductor is (a) proportional to d (b) inversely proportional to d (c) inversely proportional to d (d) none of the above

Ans: b 5. The direction of electric field due +0 positive charge is . (a) away from the charge (b) towards the charge (c) both (a) and (6) (d) none of the above Ans: a 1.A sine wave has a frequency of 50 Hz. Its angular frequency is _______ radian/second. (a) 100 n (b) 50 jt (c) 25 jt (d) 5 n Ans: a 2.The reactance offered by a capacitor to alternating current of frequency 50 Hz is 20 Q. If frequency is increased to 100 Hz, reactance becomes_____ohms. (a) 2.5 (b) 5 (c) 10 (d) 15 Ans: c 3.The period of a wave is (a) the same as frequency (b) time required to complete one cycle (c)expressed in amperes (d)none of the above Ans: b 4.The form factor is the ratio of (a) peak value to r.m.s. value (b) r.m.s. value to average value (c)average value to r.m.s. value (d)none of the above Ans: b 5.The period of a sine wave is _____ seconds. Its frequency is (a) 20 Hz (b) 30 Hz (c) 40 Hz (d) 50 Hz Ans: d 6.A heater is rated as 230 V, 10 kW, A.C. The value 230 V refers to

(a) average voltage (b) r.m.s. voltage

(c) peak voltage (d) none of the above

Ans: b

7.If two sinusoids of the same frequency but of different amplitudes and phase angles are

subtracted, the resultant is

(a) a sinusoid of the same frequency (b) a sinusoid of half the original frequency

(c) a sinusoid of double the frequency (d) not a sinusoid

Ans: a

8. The peak value of a sine wave is 200 V. Its average value is

(a) 127.4 V (b) 141.4 V

(c) 282.8 V (d)200V ANS: A

9.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

Ans: c

10.The voltage of domestic supply is 220V. This figure represents

(a) mean value (b) r.m.s. value

(c) peak value (d) average value

Ans: a

11.Two waves of the same frequency have opposite phase when the phase angle between them is

(a) 360° (b) 180°

(c) 90° (d) 0°

Ans: b

12.The power consumed in a circuit element will be least when the phase difference between the

current and voltage is

(a) 180" (b) 90°

(c) 60° (d) 0°

Ans: b

13.The r.m.s. value and mean value is the same in the case of

(a) triangular wave (b) sine wave

(c) square wave (d) half wave rectified sine wave

Ans: c

14.For the same peak value which of the following wave will 'have the highest r.m.s. value ?

(a)square wave (b)half wave rectified sine wave

(c)triangular wave (d)sine wave

Ans: a

15.For the same peak value, which of the following wave has the least mean value ?

(a) half wave rectified sine wave (b) triangular wave

(c) sine wave (d) square wave

Ans: a

16.For a sine wave with peak value Imax the r.m.s. value is

(a) 0.5 Imax (b) 0.707 (c) 0.9 (d) 1.414 Lmax

Ans: b

17.Form Factor is the ratio of

(a) average value/r.m.s. value (b) average value/peak value

(e) r.m.s. value/average value (d) r.m.s. value/peak value

Ans: c

18.Form factor for a sine wave is

(a) 1.414 (b) 0.707 (c) 1.11 (d) 0.637

Ans: c

19.For a sine wave with peak value Emax______8.30. the average value is

(a) 0.636 Emax (b) 0.707 Emax (c) 0.434 EWc (d) lAUEmax

Ans: a

20.For a frequency of 200 Hz, the time period will be

(a) 0.05 s (b) 0.005 s (c) 0.0005 s (d) 0.5 s

Ans: b

21.The phase difference between voltage and current wave through a circuit element is given as

30°. The essential condition is that

(a) both waves must have same frequency

(b) both waves must have identical peak values

(c) both waves must have zero value at the same time

(d) none of the above

Ans: a

22.The r.m.s. value of a sinusoidal A.C. current is equal to its value at an angle of______degrees.

(a) 90 (b) 60 (c) 45 (d) 30

Ans: c

23.Capacitive reactance is more when

(a) capacitance is less and frequency of supply is less

(b) capacitance is less and frequency of supply is more

(c)capacitance is more and frequency of supply is less

(d)capacitance is more and frequency of supply is more

Ans: a

24.In a series resonant circuit, the impedance of the circuit is

(a) minimum (b) maximum (c) zero (d) none of the above

Ans: a

25.Power factor of an electrical circuit is equal to

(a)R/Z (b)cosine of phase angle difference between current and voltage

(c)kW/kVA (d)ratio of useful current to total current Iw/I (e)all above Ans : e

26.The best place to install a capacitor is

(a)very near to inductive load (b)across the terminals of the inductive load

(c)far away from the inductive load (d)any where

Ans: b

27.Poor power factor

(a) reduces load handling capability of electrical system

(b) results in more power losses in the electrical system

(c) overloads alternators, transformers and distribution lines

(d) results in more voltage drop in the line

(e) results in all above

Ans: e

28.Capacitors for power factor correction are rated in

(a) kW (b) kVA

(c) kV (d) kVAR

Ans: d

29.In series resonant circuit, increasing inductance to its twice value and reducing capacitance to

its half value

(a) will change the maximum value of current at resonance

(b) will change the resonance frequency

(c) will change the impedance at resonance frequency

(d) will increase the selectivity of the circuit

Ans: d

30.Pure inductive circuit

(a)consumes some power on average

(b)does not take power at all from a line

(c)takes power from the line during some part of the cycle and then returns back to it during

other part of the cycle

(d)none of the above

Ans: c

31.Inductance affects the direct current flow

(a)only at the time of turning off (b)only at the time of turning on

(c)at the time of turning on and off (d)at all the time of operation

Ans: c

32.Inductance of a coil Varies

(a) directly as the cross-sectional area of magnetic core (b) directly as square of number of

turns

(c)directly as the permeability of the core (d)inversely as the length of the iron path

(e)as (a) to (d)

Ans: e

33.All the rules and laws of D.C. circuit also apply to A.C. circuit containing

(a)capacitance only (b)inductance only

(c)resistance only (d)all above

Ans: c

34.Time constant of an inductive circuit

(a)increases with increase of inductance and decrease of resistance

(b)increases with the increase of inductance and the increase of resistance

(c)increases with decrease of inductance and decrease of resistance

(d)increases with decrease of inductance and increase of resistance

Ans: a

35.Power factor of an inductive circuit is usually improved by connecting capacitor to it in

(a) parallel (b) series

(c) either (a) or (b) (d) none of the above

Ans: a

36.In a highly capacitive circuit the

(a) apparent power is equal to the actual power

(b) reactive power is more than the apparent power

(c) reactive power is more than the actual powetf

(d) actual power is more than its reactive power

Ans: c

37.Power factor of the following circuit will be zero

(a) resistance (b) inductance

(c) capacitance d) both (b) and (c)

Ans: d

38.Power factor of the following circuit will be unity

(a) inductance (b) capacitance

(c) resistance (d) both (a) and (b)

Ans: c

39.Power factor of the system is kept high

(a)to reduce line losses

(b)to maximise the utilization of the capacities of generators, lines and transformers

(c)to reduce voltage regulation of the line

(d)due to all above reasons

Ans: d

40.The time constant of the capacitance circuit is defined as the time during which voltage

(a) falls to 36.8% of its final steady value (b) rises to 38.6% of its final steady value

(c) rises to 63.2% of its final steady value (d) none of the above

Ans: c

41.In a loss-free R-L-C circuit the transient current is

(a) oscillating (b) square wave

(c) sinusoidal (d) non-oscillating

Ans: c

42.The r.m.s. value of alternating current is given by steady (D.C.) current which when flowing

through a given circuit for a given time produces

(a)the more heat than produced by A.C. when flowing through the same circuit

(b)the same heat as produced by A.C. when flowing through the same circuit

(c)the less heat than produced by A.C. flowing through the same circuit

(d)none of the above

Ans: b

43.The square waveform of current has following relation between r.m.s. value and average

value.

(a)r.m.s. value is equal to average value

(b)r.m.s. value of current is greater than average value

(c)r.m.s. value of current is less than average value

(d)none of the above

Ans: a

44.The double energy transient occur in the

(a)purely inductive circuit (b)R-L circuit

(c)R-C circuit (d) R-L-C circuit

Ans: d

45.The transient currents are associated with the

(a)changes in the stored energy in the inductors and capacitors

(b)impedance of the circuit

(c)applied voltage to the circuit

(d)resistance of the circuit

Ans: a

46.The power factor at resonance in R-L- C parallel circuit is

(a) zero (b) 0.08 lagging

(c) 0.8 leading (d) unity

Ans: d

47.In the case of an unsymmetrical alternating current the average value must always be taken

over

(a) unsymmetrical part of the wave form (b) the quarter cycle

(c) the half cycle (d) the whole cycle

Ans: d

48.In a pure resistive circuit

(a)current lags behind the voltage by 90° (b)current leads the voltage by 90°

(c)current can lead or lag the voltage by 90° (d) current is in phase with the voltage

Ans: d

49.In a pure inductive circuit

(a)the current is in phase with the voltage (b)the current lags behind the voltage by 90°

(c)the current leads the voltage by 90° (d)the current can lead or lag by 90°

Ans: b

50.In a circuit containing R, L and C, power loss can take place in

(a) C only (b) L only

(c) R only (d) all above

Ans: c

1. The insulating material for a cable should have (a) low cost (b) high dielectric strength (c) high mechanical strength (d) all of the above Ans: d 2. Which of the following protects a cable against mechanical injury ? (a) Bedding (b) Sheath (c) Armouring (d) None of the above Ans: c 3. Which of the following insulation is used in cables ? (a) Varnished cambric (b) Rubber (c) Paper (d) Any of the above Ans: d 4. Empire tape is (a) varnished cambric (b) vulcanised rubber (c) impregnated paper (d) none of the above Ans: a 5. The thickness of the layer of insulation on the conductor, in cables, depends upon (a) reactive power (b) power factor (c) voltage (d) current carrying capacity Ans: c 1.The S.I. unit of power is (a) henry (b) coulomb (c) watt (d) watt-hour Ans: c 2. Electric pressure is also called (a) resistance (b) power (c) voltage (d) energy Ans: c 3.The substances which have a large number of free electrons and offer a low resistance are called (a) insulators (b) inductors (c)semi-conductors (d)conductors Ans: d 4.Out of the following which is not a poor conductor ? (a) Cast iron (b) Copper (c) Carbon (d) Tungsten Ans: b 5.Out of the following which is an insulating material ? (a) Copper (b) Gold (c) Silver (d) Paper

Ans: d 1. Laminations of core are generally made of (a) case iron (b) carbon (c)silicon steel (d)stainless steel Ans: c 2. Which of the following could be lamina-proximately the thickness of lamina-tions of a D.C. machine ? (a)0.005 mm (b)0.05 mm (c)0.5 m (d)5 m Ans: c 3. The armature of D.C. generator is laminated to (a) reduce the bulk (b) provide the bulk (c)insulate the core (d)reduce eddy current loss Ans: d 4.The resistance of armature winding depends on (a) length of conductor (b) cross-sectional area of the conductor (c)number of conductors (d)all of the above Ans: d 5.The field coils of D.C. generator are usually made of (a) mica (b) copper (c) cast iron (d) carbon Ans: b 1. Kirchhoff s current law states that (a) net current flow at the junction is positive (b) Hebraic sum of the currents meeting at the junction is zero (c) no curreht can leave the junction without some current entering it. (d) total sum of currents meeting at the junction is zero Ans: b 2. According to Kirchhoffs voltage law, the algebraic sum of all IR drops and e.m.fs. in any closed loop of a network is always (a) negative (b) positive (c) determined by battery e.m.fs. (d) zero Ans: d 3. Kirchhoffs current law is applicable to only (a) junction in a network (b) closed loops in a network (c) electric circuits (d) electronic circuits Ans: a

4. Kirchhoffs voltage law is related to (a) junction currents (b) battery e.m.fs. (c) IR drops (d) both (b) and (c) (e) none of the above Ans: d 5. Superposition theorem can be applied only to circuits having (a) resistive elements (b) passive elements (c) non-linear elements (d) linear bilateral elements Ans: d 1.Speed of the stator field of an Induction motor is (a) Synchronous speed (b) Any speed (c) Less than Synchronous (d) Slip Speed Ans(a) Synchronous speed 2.Difference in speed between stator field and rotor (a) Full load speed (b)No load speed (c)Slip (d) Regulation Ans:(c)Slip 3.Frequency of current in rotor (a)Supply frequency (b)Less than supply frequency (c)Greater than supply frequency (d)Slip frequency Ans;(d) Slip Frequency 4. Shape of the torque slip curve is (a) Rectangular Hyperbola (b)Parabola (c)Sine

(d) Cosine Ans;(a) Rectangular Hyperbola 5.Machine with negative slip (a)Induction Motor (b) Brake (c)Induction Generator (d)Synchronous machine Ans(c) Induction Generator 1.The property of coil by which a counter e.m.f. is induced in it when the current through the coil changes is known as (a) self-inductance (b) mutual inductance (c) series aiding inductance (d) capacitance Ans: a 2.As per Faraday's laws of electromagnetic induction, an e.m.f. is induced in a conductor whenever it (a) lies perpendicular to the magnetic flux (b) lies in a magnetic field (e) cuts magnetic flux (d) moves parallel to the direction of the magnetic field Ans: c 3.Which of the following circuit element stores energy in the electromagnetic field ? (a) Inductance (b) Condenser (c) Variable resistor (d) Resistance Ans: a 4.The inductance of a coil will increase under all the following conditions except (a) when more length for the same number of turns is provided (6) when the number of turns of the coil increase (c) when more area for each turn is provided (d) when permeability of the core increases Ans: a 5. Higher the self-inductance of a coil, (a) lesser its weber-turns (b) lower the e.m.f. induced (c) greater the flux produced by it (d) longer the delay in establishing steady current. Ans: d 1. The converse of hardness is known as (a) malleability (b) toughness (c) softness (d) none of the above Ans: c 2. On which of the following factors does the resistivity of a material depend ? (a)Resistance of the conductor (b)Area of the conductor section (c)Length of the conductor (d) All of the above Ans: d

3. Is a negatively charged particle present in an atom. (a) Proton (b)Neutron (c)Electron (d) None of the above Ans: c 4. The formula ____ determines the number of electrons that can be accommodated in any level. (a) 2n2 (b)4n2 (c)2n3 (d)4ns Ans: a 5. The tiny block formed by the arrangement of a small group of atoms is called the (a) unit cell (b)space lattice (c)either (a) or (b) (d) none of the above Ans: a 1."The mass of an ion liberated at an electrode is directly proportional to the quantity of electricity". The above statement is associated with (a)Newton's law (b)Faraday's law of electromagnetic (c)Faraday's law of electrolysis (d)Gauss's law Ans: c 2.The charge required to liberate one gram equivalent of any substance is known as ______ constant (a) Time b) Faraday's (c) Boltzman Ans: b 3.During the charging of a lead-acid cell (a) its voltage increases (b) it gives out energy (c) its cathode becomes dark chocolate brown in colour (d) specific gravity of H2SO4 decreases Ans: a 4.The capacity of a lead-acid cell does not depend on its (a) temperature (b) rate of charge (c) rate of discharge (d) quantity of active material Ans: b 5.During charging the specific gravity of the electrolyte of a lead-acid battery (a) increases (b) decreases (c) remains the same (d) becomes zero Ans: a 1. Which of the following is an advantage of heating by electricity ? (a) Quicker operation (b) Higher efficiency (c) Absence of flue gases

(d) All of the above Ans: d 2. ________ has the highest value of thermal conductivity. (a) Copper (b) Aluminium (c) Brass (d) Steel Ans: a 3. Which of the following heating methods has maximum power factor ? (a) Arc heating (b) Dielectric heating (c) Induction heating (d) Resistance heating Ans: d 4 method has leading power factor (a) Resistance heating (b) Dielectric heating (c) Arc heating (d) Induction heating Ans: b 5 is used for heating non-conducting materials. (a) Eddy current heating (b) Arc heating (c) Induction heating (d) Dielectric heating Ans: d 1. An air gap is usually inserted in magnetic circuits to (a) increase m.m.f. (b) increase the flux (c) prevent saturation (d) none of the above Ans: c 2. The relative permeability of a ferromagnetic material is (a) less than one (b) more than one (c) more than 10 (d) more than 100 or 1000 Ans: d 3. The unit of magnetic flux is (a) henry

(b) weber (c) ampereturn/weber (d) ampere/metre Ans: b 4. Permeability in a magnetic circuit corresponds to______ in an electric circuit. (a) resistance (b) resistivity (c) conductivity (d) conductance Ans: c 5. Point out the wrong statement. Magnetic leakage is undesirable in electric machines because it (a) lowers their power efficiency (b) increases their cost of manufacture (c) leads to their increased weight (d) produces fringing Ans: a 1. An air gap is usually inserted in magnetic circuits to (a) increase m.m.f. (b) increase the flux (c) prevent saturation (d) none of the above Ans: c 2. The relative permeability of a ferromagnetic material is (a) less than one (b) more than one (c) more than 10 (d) more than 100 or 1000 Ans: d 3. The unit of magnetic flux is (a) henry (b) weber (c) ampereturn/weber (d) ampere/metre Ans: b 4. Permeability in a magnetic circuit corresponds to______ in an electric circuit. (a) resistance (b) resistivity (c) conductivity (d) conductance Ans: c

5. Point out the wrong statement. Magnetic leakage is undesirable in electric machines because it (a) lowers their power efficiency (b) increases their cost of manufacture (c) leads to their increased weight (d) produces fringing Ans: a 1. An air gap is usually inserted in magnetic circuits to (a) increase m.m.f. (b) increase the flux (c) prevent saturation (d) none of the above Ans: c 2. The relative permeability of a ferromagnetic material is (a) less than one (b) more than one (c) more than 10 (d) more than 100 or 1000 Ans: d 3. The unit of magnetic flux is (a) henry (b) weber (c) ampereturn/weber (d) ampere/metre Ans: b 4. Permeability in a magnetic circuit corresponds to______ in an electric circuit. (a) resistance (b) resistivity (c) conductivity (d) conductance Ans: c 5. Point out the wrong statement. Magnetic leakage is undesirable in electric machines because it (a) lowers their power efficiency (b) increases their cost of manufacture (c) leads to their increased weight (d) produces fringing Ans: a 1. An air gap is usually inserted in magnetic circuits to (a) increase m.m.f. (b) increase the flux (c) prevent saturation (d) none of the above

Ans: c 2. The relative permeability of a ferromagnetic material is (a) less than one (b) more than one (c) more than 10 (d) more than 100 or 1000 Ans: d 3. The unit of magnetic flux is (a) henry (b) weber (c) ampereturn/weber (d) ampere/metre Ans: b 4. Permeability in a magnetic circuit corresponds to______ in an electric circuit. (a) resistance (b) resistivity (c) conductivity (d) conductance Ans: c 5. Point out the wrong statement. Magnetic leakage is undesirable in electric machines because it (a) lowers their power efficiency (b) increases their cost of manufacture (c) leads to their increased weight (d) produces fringing Ans: a 1. An air gap is usually inserted in magnetic circuits to (a) increase m.m.f. (b) increase the flux (c) prevent saturation (d) none of the above Ans: c 2. The relative permeability of a ferromagnetic material is (a) less than one (b) more than one (c) more than 10 (d) more than 100 or 1000 Ans: d 3. The unit of magnetic flux is (a) henry (b) weber

(c) ampereturn/weber (d) ampere/metre Ans: b 4. Permeability in a magnetic circuit corresponds to______ in an electric circuit. (a) resistance (b) resistivity (c) conductivity (d) conductance Ans: c 5. Point out the wrong statement. Magnetic leakage is undesirable in electric machines because it (a) lowers their power efficiency (b) increases their cost of manufacture (c) leads to their increased weight (d) produces fringing Ans: a 1. An air gap is usually inserted in magnetic circuits to (a) increase m.m.f. (b) increase the flux (c) prevent saturation (d) none of the above Ans: c 2. The relative permeability of a ferromagnetic material is (a) less than one (b) more than one (c) more than 10 (d) more than 100 or 1000 Ans: d 3. The unit of magnetic flux is (a) henry (b) weber (c) ampereturn/weber (d) ampere/metre Ans: b 4. Permeability in a magnetic circuit corresponds to______ in an electric circuit. (a) resistance (b) resistivity (c) conductivity (d) conductance Ans: c 5. Point out the wrong statement.

Magnetic leakage is undesirable in electric machines because it (a) lowers their power efficiency (b) increases their cost of manufacture (c) leads to their increased weight (d) produces fringing Ans: a 1. An air gap is usually inserted in magnetic circuits to (a) increase m.m.f. (b) increase the flux (c) prevent saturation (d) none of the above Ans: c 2. The relative permeability of a ferromagnetic material is (a) less than one (b) more than one (c) more than 10 (d) more than 100 or 1000 Ans: d 3. The unit of magnetic flux is (a) henry (b) weber (c) ampereturn/weber (d) ampere/metre Ans: b 4. Permeability in a magnetic circuit corresponds to______ in an electric circuit. (a) resistance (b) resistivity (c) conductivity (d) conductance Ans: c 5. Point out the wrong statement. Magnetic leakage is undesirable in electric machines because it (a) lowers their power efficiency (b) increases their cost of manufacture (c) leads to their increased weight (d) produces fringing Ans: a 1. An air gap is usually inserted in magnetic circuits to (a) increase m.m.f. (b) increase the flux (c) prevent saturation (d) none of the above Ans: c

2. The relative permeability of a ferromagnetic material is (a) less than one (b) more than one (c) more than 10 (d) more than 100 or 1000 Ans: d 3. The unit of magnetic flux is (a) henry (b) weber (c) ampereturn/weber (d) ampere/metre Ans: b 4. Permeability in a magnetic circuit corresponds to______ in an electric circuit. (a) resistance (b) resistivity (c) conductivity (d) conductance Ans: c 5. Point out the wrong statement. Magnetic leakage is undesirable in electric machines because it (a) lowers their power efficiency (b) increases their cost of manufacture (c) leads to their increased weight (d) produces fringing Ans: a 1. Which of the following are the applications of D.C. system ? (a) Battery charging work (b) Arc welding (c) Electrolytic and electro-chemical processes (d) Arc lamps for search lights (e) All of the above Ans: e 2. Which of the following methods may be used to convert A.C. system to D.C. ? (a) Rectifiers (b) Motor converters (c) Motor-generator sets (d) Rotary converters (e) All of the above Ans: e 3. In a single phase rotary converter the number of slip rings will be (a) two (b) three (c) four (d) six (e) none Ans: a 4. A synchronous converter can be started

(a) by means of a small auxiliary motor (b) from AC. side as induction motor (c) from D.C. side as D.C. motor (d) any of the above methods (e) none of the above methods Ans: d 5. A rotary converter is a single machine with (a) one armature and one field (b) two armatures and one field (c) one armature and two fields (d) none of the above Ans: a 1. By which of the following systems electric power may be transmitted ? (a) Overhead system (b) Underground system (c) Both (a) and (b) (d) None of the above Ans: c 2 are the conductors, which connect the consumer's terminals to the distribution (a) Distributors (b) Service mains (c) Feeders (d) None of the above Ans: b 3. The underground system cannot be operated above (a) 440 V (b) 11 kV (c) 33 kV (d) 66 kV Ans: d 4. Overhead system can be designed for operation upto (a) 11 kV (b) 33 kV (c) 66 kV (d) 400 kV Ans: c 5. If variable part of annual cost on account of interest and depreciation on the capital outlay is equal to the annual cost of electrical energy wasted in the conductors, the total annual cost will be minimum and the corresponding size of conductor will be most economical. This statement is known as (a) Kelvin's law (b) Ohm's law (c) Kirchhoffs law (d) Faraday's law (e) none of the above Ans: a 1. In an open loop control system

(a) Output is independent of control input (b) Output is dependent on control input

(c) Only system parameters have effect on the control output

(d) None of the above

Ans: a

2. For open control system which of the following statements is incorrect ?

(a) Less expensive

(b) Recalibration is not required for maintaining the required quality of the output

(c) Construction is simple and maintenance easy

(d) Errors are caused by disturbances

Ans: b

3. A control system in which the control action is somehw dependent on the output is known as

(a) Closed loop system (b)Semiclosed loop system (c)Open system (d)None of the above

Ans: a

4. In closed loop control system, with positive value of feedback gain the overall gain of the

system will

(a) decrease (b) increase (c) be unaffected (d) any of the above

Ans: a

5. Which of the following is an open loop control system ?

(a) Field controlled D.C. motor (b) Ward leonard control (c)Metadyne (d)Stroboscope

Ans: a

6. Which of the following statements is not necessarily correct for open control system ?

(a) Input command is the sole factor responsible for providing the control action

(b) Presence of non-linearities causes malfunctioning

(c) Less expensive

(d) Generally free from problems of non-linearities

Ans: b

7. In open loop system

(a) the control action depends on the size of the system

(b) the control action depends on system variables

(c) the control action depends on the input signal

(d) the control action is independent of the output

Ans: d

8 has tendency to oscillate.

(a) Open loop system (b)Closed loop system (c) Both (a) and (b) (d)Neither (a) nor (b)

Ans: b

9. A good control system has all the following features except

(a) good stability (b) slow response (c) good accuracy (d) sufficient power handling capacity

Ans: b

10. A car is rtyining at a constant speed of 50 km/h, which of the following is the feedback

element for the driver ?

(a) Clutch (b) Eyes (c) Needle of the speedometer (d)Steering wheel (e)None of the above

Ans: c

11. The initial response when tne output is not equal to input is called

(a) Transient response (b)Error response (c) Dynamic response (d) Either of the above

Ans: a

12. A control system working under unknown random actions is called

(a) computer control system (b) digital data system

(c) stochastic control system (d) adaptive control system

Ans: c

13. An automatic toaster is a ______ loop control system.

(a) open (b) closed (c) partially closed (d) any of the above

Ans: a

14. Any externally introduced signal affecting the controlled output is called a

(a) feedback (b) stimulus (c) signal (d) gain control

Ans: b

15. A closed loop system is distinguished from open loop system by which of the following ?

(a) Servomechanism (b) Feedback (c) Output pattern (d) Input pattern

Ans: b

16 is a part of the human temperature control system.

(a) Digestive system (b) Perspiration system (c) Ear (d) Leg movement

Ans: b

17. By which of the following the control action is determined when a man walks along a path ?

(a) Brain (b) Hands (c) Legs (d) Eyes

Ans: d

18 is a closed loop system.

(a) Auto-pilot for an aircraft (b) Direct current generator (c)Car starter (d)Electric switch

Ans: a

19. Which of the following devices are commonly used as error detectors in instruments ?

(a) Vernistats (b) Microsyns (c)Resolvers (d) Any of the above

Ans: d

20. Which of the following should be done to make an unstable system stable ?

(a) The gain of the system should be decreased

(b) The gain of the system should be increased

(c) The number of poles to the loop transfer function should be increased

(d) The number of zeros to the loop transfer function should be increased

Ans: b

21 increases the steady state accuracy.

(a) Integrator (b)Differentiator (c)Phase lead compensator (d) Phase lag compensator

Ans: a

22. A.C. servomotor resembles

(a) two phase induction motor (b)Three phase induction motor (c)direct current series motor

(d) universal motor

Ans: a

23. As a result of introduction of negative feedback which of the following will not decrease ?

(a) Band width (b)Overall gain (c)Distortion (d) Instability

Ans: a

24. Regenerative feedback implies feedback with

(a) oscillations (b) step input (c) negative sign (d) positive sign

Ans: d

25. The output of a feedback control system must be a function of

(a) reference and output (b)reference and input (c)input and feedback signal

(d) output and feedback signal

Ans: a

26 is an open loop control system.

(a) Ward Leonard control (b)Field controlled D.C. motor (c)Stroboscope (d)Metadyne

Ans: b

27. A control system with excessive noise, is likely to suffer from

(a) saturation in amplifying stages (b)loss of gain (c)vibrations (d)oscillations

Ans: a

28. Zero initial condition for a system means

(a) input reference signal is zero (b) zero stored energy

(c) ne initial movement of moving parts

(d) system is at rest and no energy is stored in any of its components

Ans: d

29. Transfer function of a system is used to calculate which of the following ?

(a) The order of the system (b) The time constant

(c) The output for any given input (d) The steady state gain

Ans: c

30. The band width, in a feedback amplifier.

(a) remains unaffected (b) decreases by the same amount as the gain increase

(c) increases by the sane saaaajajt as the gain decrease

(d) decreases by the same amount as the gain decrease

Ans: c

31. On which of the following factors does the sensitivity of a closed loop system to gain

changes and load disturbances depend ?

(a) Frequency (b) Loop gain (c) Forward gain (d) All of the above

Ans: d

32. The transient response, with feedback system,

(a) rises slowly (b) rises quickly (c) decays slowly (d) decays quickly

Ans: d

33. The second derivative input signals modify which of the following ?

(a) The time constant of the system (b) Damping of the system

(c) The gain of the system (d) The time constant and suppress the oscillations

(e) None of the above

Ans: d

34. Which of the following statements is correct for any closed loop system ?

(a) All the co-efficients can have zero value

(b) All the co-efficients are always non-zero

(c) Only one of the static error co-efficients has a finite non-zero value

(d) None of the above

Ans: c

35. Which of the following statements is correct for a system with gain margin close to unity or

a phase margin close to zero ?

(a) The system is relatively stable (b) The system is highly stable

(c) The system is highly oscillatory (d) None of the above

Ans: c

36. Due to which of the following reasons excessive bond width in control systems should be

avoided ?

(a) It leads to slow speed of response (b) It leads to low relative stability

(c) Noise is proportional to band width (d) None of the above

Ans: c

37. In a stable control system backlash can cause which of the following ?

(a) Underdamping (b) Overdamping

(c) Poor stability at reduced values of open loop gain (d) Low-level oscillations

Ans: d

38. In an automatic control system which of the following elements is not used ?

(a) Error detector (b)Final control element (c)Sensor (d)Oscillator

Ans: d

39. In a control system the output of the controller is given to

(a) final control element (b)amplifier (c)comparator (d)sensor

(e) none of the above

Ans: a

40. A controller, essentially, is a

(a) sensor (b) clipper (c) comparator (d) amplifier

Ans: c

41. Which of the following is the input to a controller ?

(a) Servo signal (b) Desired variable value (c) Error signal (d) Sensed signal

Ans:

42. The on-off controller is a _____ system.

(a) digital (b) linear (c) non-linear (d) discontinuous

Ans:

43. The capacitance, in force-current analogy, is analogous to

(a) momentum (b) velocity (c) displacement (d) mass

Ans: d

44. The temperature, under thermal and electrical system analogy, is considered analogous to

(a) voltage (b) current (c) capacitance (d) charge (e) none of the above

Ans: a

45. In electrical-pneumatic system analogy the current is considered analogous to

(a) velocity (b) pressure (c) air flow (d) air flow rate

Ans: d

46. In liquid level and electrical system analogy, voltage is considered analogous to

(a) head (b) liquid flow (c) liquid flow rate (d) none of the above

Ans: a

47. The viscous friction co-efficient, in force-voltage analogy, is analogous to

(a) charge (b)resistance (c)reciprocal of inductance (d)reciprocal of conductance

(e) none of the above

Ans: b

48. In force-voltage analogy, velocity is analogous to

(a) current (b)charge (c)inductance (d) capacitance

Ans: a

49. In thermal-electrical analogy charge is considered analogous to

(a) heat flow (b) reciprocal of heat flow (c) reciprocal of temperature (d)temperature

(e) none of the above

Ans: d

50. Mass, in force-voltage analogy, is analogous to

(a) charge (b) current (c) inductance (d) resistance

Ans: c

1.The number of digits in octal system is

a.8 b.7 c.10 d. none

Ans:-a

2..The number of digits in Hexadecimal system is

a.15 b.17 c.16 d. 8

Ans:-c

3.The number of bits in a nibble is

a.16 b.5 c.4 d.8

Ans:-c

4.The digit F in Hexadecimal system is equivalent to —— in decimal system

a.16 b.15 c.17 d. 8

Ans:-b

5.Which of the following binary numbers is equivalent to decimal 10

a.1000 b.1100 c.1010 d.1001

Ans:-c

6.The number FF in Hexadecimal system is equivalent to —— in decimal system

a.256 b.255 c.240 d.239

Ans:-b

7.IC s are

a. analog b. digital c. both analog and digital d. mostly analog

Ans:-c

8.The rate of change of digital signals between High and Low Level is

a. very fast b. fast c. slow d. very slow

Ans:-a

9. Digital circuits mostly use

a. Diodes

b. Bipolar transistors

c. Diode and Bipolar transistors

d. Bipolar transistors and FETs

Ans:-c

10.Logicpulser

a. generates short duration pulses

b. generate long duration pulses

c. generates long and short duration

d. none of above

Ans:-b

11.What is the output state of an OR gate if the inputs are 0 and 1?

a.0

b.1

c.3

d.2

Ans:-b

12.What is the output state of an AND gate if the inputs are 0 and 1?

a.0

b.1

c.3

d.2

Ans:-a

13.A NOT gate has…

a. Two inputs and one output

b. One input and one output

c. One input and two outputs

d. none of above

Ans:-b

14.An OR gate has…

a. Two inputs and one output

b. One input and one output

c. One input and two outputs

d. none of above

Ans:-a

15.The output of a logic gate can be one of two _____?

a. Inputs

b. Gates

c.States

d. none

Ans:-a

16.Logic states can only be ___ or 0.

a. 3

b. 2

c.1

d.0

Ans:-c

17.The output of a ____ gate is only 1 when all of its inputs are 1

a. NOR

b. XOR

c. AND

d. NOT

Ans:-c

18.A NAND gate is equivalent to an AND gate plus a …. gate put together.

a. NOR

b. NOT

c. XOR

d. none

Ans:-b

19.Half adder circuit is ______?

a. Half of an AND gate

b. A circuit to add two bits together

c. Half of a NAND gate

d. none of above

Ans:-b

20. Numbers are stored and transmitted inside a computer in

a. binary form

b. ASCII code form

c. decimal form

d. alphanumeric form

Ans:-a

21.The decimal number 127 may be represented by

a. 1111 1111B

b. 1000 0000B

c. EEH

d. 0111 1111

Ans:-d

22.. A byte corresponds to

a. 4 bits

b. 8 bits

c. 16 bits

d. 32 bits

Ans:-b

23.A gigabyte represents

a.1 billion bytes

b. 1000 kilobytes

c. 230 bytes

d. 1024 bytes

Ans:-a

24. A megabyte represents

a. 1 million bytes

b. 1000 kilobytes

c. 220 bytes

d. 1024 bytes

Ans:-a

25.. A Kb corresponds to

a. 1024 bits

b. 1000 bytes

c.210 bytes

d. 210 bits

Ans:-b

26.A parity bit is

a. used to indicate uppercase letters

b. used to detect errors

c. is the first bit in a byte

d. is the last bit in a byte

Ans:-b

27. Which of these devices are two state.

a. lamp

b. punched card

c. magnetic tape

d. all the above

Ans:-a

28.The output impedance of of a logic pulser is

a. low

b. high

c. may be low or high

d. none of above

Ans:-c

29.In hexadecimal number system,A is equal to decimal number

a.10

b.11

c.17

d.18

Ans:-a

30.Hexadecimal number F is equal to octal number

a.15

b.16

c.17

d.18

Ans:-c

31.Hexadecimal number E is equal to binary number

a.1110

b.1101

c.1001

d.1111

Ans:-a

32.Binary number 1101 is equal to octal number

a.15

b.16

c.17

d.14

Ans:-a

33.Octal number 12 is equal to decimal number

a.8

b.11

c.9

d. none

Ans:-d

34.Decimal number 10 is equal to binary number

a.1110

b.1000

c.1001

d.1010

Ans:-d

35.Binary number 110011011001 is equal to decimal number

a.3289

b.2289

c.1289

d.289

Ans:-a

36.1111+11111=

a.101111

b.101110

c.111111

d.011111

Ans:-b

37.Binary multiplication 1*0=

a.1

b.0

c.10

d.11

Ans:-b

38.110012 -100012=

a.10000

b.01000

c.00100

d.00001

Ans:-a

39.10112*1012=

a.55

b.45

c.35

d.25

Ans:-a

40.1110112*100012=

a.111101101

b.111101100

c.111110

d.1100110

Ans:-b

41.4 bits is equal to

a. 1 nibble

b.1 byte

c. 2 byte

d. none of above

Ans:-a

42. which is non-volatile memory

a. RAM

b. ROM

c. both

d. none

Ans:-b

43. The contents of these chips are lost when the computer is switched off?

a. ROM chips

b. RAM chips

c. DRAM chips

d. none of above

Ans:-b

44.What are responsible for storing permanent data and instructions.?

a. RAM chips

b. ROM chips

c. DRAM chips

d. none of above

Ans:-b

45. Which parts of the computer perform arithmetic calculations?

a. ALU

b. Registers

c. Logic bus

d. none of above

Ans:-a

46.How many bits of information can each memory cell in a computer chip hold?

a. 0 bits

b. 1 bit

c. 8 bits

d. 2 bits

Ans:-b

47.What type of computer chips are said to be volatile?

a. RAM chips

b. ROM chips

c. DRAM

d. none of above

Ans:-a

48.Which generation of computer uses more than one microprocessor?

a. Second generation

b. Fifth generation

c.Third generation

d .none of above

Ans:-c

49.Which generation of computer developed using integrated circuits?

a. Second generation

b. Fifth generation

c. Third generation

d. none of above

Ans:-a

50.Which generation of computer was developed from microchips?

a. Second generation

b. Third generation

c. Fourth generation

d. none of above Ans:-b

51. The capacitor preferred for high frequency circuits is

(a) air capacitor

(b) mica capacitor

(c) electrolytic capacitor

(d) none of the above

Ans: b

52. The capacity of capacitor bank used in power factor correction is expressed in terms of

(a) kW

(b) kVA

(c) kVAR

(d) volts

Ans: c

53. While testing a capacitor with ohm-metre, if the capacitor shows charging, but the final resistance

reading is appreciably less than normal, it can be concluded that the capacitor is

(a) short-circuited

(b) open circuited

(c) alright

(d) leaky

Ans: d

54. If a 6 (iF capacitor is charged to 200 V, the charge in coulombs will be

(a) 800 uC

(b) 900 uC

(c) 1200 uC

(d) 1600 uC

Ans: c

55. Which capacitor will be physically smaller for the same ratings ?

(a) Ceramic capacitor

(b) Paper capacitor

(c) Both will be of equal size

(d) None of the above

Ans: a

56. What is the value of capacitance that must be connected in parallel with 50 pF condenser to

make an equivalent capacitance of 150 pF ?

(a) 50 pF

(b) 100 pF

(c) 150 pF

(d) 200 pF

Ans: b

57. A mica capacitor and a ceramic capacitor both have the same physical dimensions. Which will

have more value of capacitance ?

(a) Ceramic capacitor

(b) Mica capacitor

(c) Both will have identical value of capacitance

(d) It depends on applied voltage

Ans: a

58. Which of the following material has least value of dielectric constant ?

(a) Ceramics

(b) Oil

(c) Glass

(d) Paper

Ans: b

59. Which of the following capacitors will have the least value of breakdown voltage ?

(a) Mica

(b) Paper

(c) Ceramic

(d) Electrolytic

Ans: d

3.73. The breakdown voltage for paper capacitors is usually

(a) 20 to 60 volts

(b) 200 to 1600 volts

(c) 2000 to 3000 volts

(d) more than 10000 volts

Ans:

60. Dielectric constant for mica is nearly

(a) 200

(b) 100

(c) 3 to 8

(d) 1 to 2

Ans: c

61. The value of dielectric constant for vacuum is taken as

(a) zero

(b) 1

(c) 4

(d) 10

Ans: b

62. Which of the following capacitors is marked for polarity ?

(a) Air

(b) Paper

(c) Mica

(d) Electrolytic

Ans: d

63. Which of the following capacitors can be used for temperature compensation ?

(a) Air capacitor

(b) Ceramic capacitor

(c) Paper capacitor

(d) None of the above

Ans: b

64. Which of the following statements is incorrect ?

(a) The thinner the dielectric, the more the capacitance and the lower the voltage breakdown rating for

a capacitor .

(b) A six dot mica capacitor colour coded white, green, black, red and yellow has the capacitance value

of 500 pF

(c) Capacitors in series provide less capacitance but a higher voltage breakdown rating for the

combina¬tion

(d) A capacitor can store charge be¬cause it has a dielectric between two conductors

Ans: b

65. Paper capacitors usually have a tolerance of

(a) ± 5%

(b) ± 10%

(c) ± 15%

(d) ± 20%

Ans: b

66. For closer tolerances which of the following capacitors is usually preferred ?

(a) Paper capacitor

(b) Mica capacitor

(c) Ceramic disc capacitor

(d) None of the above

Ans: b

67. The electrostatic force between two charges of one coulomb each and placed at a distance of

0.5 m will be

(a) 36 x 10fa

(b) 36 x 107 N

(c) 36 x 108 N

(d) 36 x 109 N

Ans: d

68. The units of volume charge density are

(a) Coulomb/metre

(b) Coulomb/metre

(c) Coulomb/metre

(d) Coulomb/metre

Ans: c

69. "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

(a) Gauss's law

(b) Kirchhoff s law

(c) Faraday's law

(d) Lenz's law

Ans: a

70. Dielectric strength of mica is

(a) 10 to 20 kV/mm

(6) 30 to 50 kV/mm

(c) 50 to 200 kV/mm

(d) 300 to 500 kV/mm

Ans: c

71. The dielectric constant (relative permittivity) of glass is given by

(a) 0.1 to 0.4

(b) 0.5 to 1.0

(c) 2.0 to 4.0

(d) 5 to 100

Ans: d

72 capacitors are mainly used for radio frequency tuning.

(a) Paper

(b) Air

(c) Mica

(d) Electrolytic

Ans: b

73. capacitors can be used only for D.C.

(a) Air

(b) Paper

(e) Mica

(d) Electrolytic

Ans: d

74. capacitors are used in transistor circuits.

(a) Ceramic

(b) Paper

(c) Air

(d) Electrolytic

Ans: a

75. capacitors are used for audio frequency and radio frequency coupling and tuning.

(a) Air

(b) Mica

(c) Plastic film

(d) Ceramic

Ans: b

76. The inverse of capacitance is called

(a) reluctance

(b) conductance

(c) susceptance

(d) elastance

Ans: d

77. When the dielectric is homogeneous,the potential gradient is

(a) uniform

(b) non-uniform

(c) zero

(d) any of the above

Ans: a

78. The potential gradient across the material of low permittivity is than across the material of high

permittivity.

(a) smaller

(b) greater

(c) both (a) and (b)

(d) none of the above

Ans: b

79. ________field is associated with the capacitor.

(a) Electric

(b) Magnetic

(c) Both (a) and (b)

(d) None of the above

Ans: a

80. A capacitor having capacitance of 5 uF is charged to a potential difference of 10,000 V. The energy

stored in the capacitor is

(a) 50 joules

(b) 150 joules

(c) 200 joules

(d) 250 joules

Ans: d