EE [ONGC]-2009 paper 1 FOR COMPLETE SOLUTION · PDF fileMMF method gives optimistic results 1 under ges in armature n . ... in induced emf can be eliminated by using coils show chorded

EE [ONGC]-2009 paper

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ELECTRICAL ENGINEERING1. A single phase transformer is connected to a

supply of voltage V and frequency f and is supplying a load, connected across its secondary winding. If the supply voltage is reduced from V to V/2, the flux established in the core will (a.) decrease by nearly 50%(b.) increase by nearly 50%(c.) remain unchanged (d.) be affected by amount of load and not by

the applied voltage 2. Under magnetic saturation of the core of a

transformer, the reactance parameters of its equivalent circuit are affected such that(a.) X1 and X2 increase while X

change (b.) X1 and X2 do not change while X

decreases (c.) X1 and X2 do not change while X

increases (d.) X1 and X2 decreases while X

change 3. A single phase 2000/200 V, 10 kVA, two

winding transformer is reconnected as a stepup autotransformer with 2000 V winding as primary. The kVA rating of the autotransformer shall be (a.) 10 kVA (b.) 11 kVA (c.) 110 kVA (d.) 220 kVA

4. The power factor at which power is drawna transformer is (a.) very low under O.C. test but high under

S.C. test (b.) high under O.C. test but low under S.C.

test (c.) low both under O.C. and S.C. tests(d.) high both under O.C. and S.C. tests

5. The O.C.C. of a shunt d.c. generator is represented by E = 12+66I. If the field resistance is 70 ohms, the nothe generator will be

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ELECTRICAL ENGINEERINGA single phase transformer is connected to a supply of voltage V and frequency f and is supplying a load, connected across its

If the supply voltage is reduced from V to V/2, the flux established in

decrease by nearly 50% increase by nearly 50%

be affected by amount of load and not by

Under magnetic saturation of the core of a nsformer, the reactance parameters of its

equivalent circuit are affected such that increase while Xm does not

do not change while Xm

do not change while Xm

decreases while Xm does not

A single phase 2000/200 V, 10 kVA, two winding transformer is reconnected as a step-up autotransformer with 2000 V winding as primary. The kVA rating of the

The power factor at which power is drawn by

ery low under O.C. test but high under

high under O.C. test but low under S.C.

low both under O.C. and S.C. tests high both under O.C. and S.C. tests

The O.C.C. of a shunt d.c. generator is represented by E = 12+66I. If the field resistance is 70 ohms, the no-load voltage of

(a.) 144 V (b.) 210 V (c.) 220 V (d.) 288 V

6. In d.c. shunt motors, the developed torque is proportional to (a.) induced e.m.f. (b.) armature current(c.) output power (d.) line current

7. The speed of a separately excited d.c. motor can be controlled below base speed by (a) armature resistance control and (b) supply voltage control. What happens to the slope of modified speed-torque characteristicsthe two methods? (a.) It changes in both types of control(b.) It remains unchanged in both types of

control (c.) It remains unchanged in armature

resistance control while changes in supply voltage control

(d.) It remains unchanged in supply voltage control while chanresistance control

8. The polarity of interpoles used in d.c. machines is (a.) same as the main pole ahead in

generators while opposite of the main pole ahead in motors

(b.) same as the main pole ahead ion motors while opposite of the main pole ahead igenerators

(c.) same as the main pole ahead in both motors and generators

(d.) opposite of the main pole ahead in both motors and generators

9. In synchronous generators, examine the following statements about voltage regulation: 1. Synchronous impedance method gives

pessimistic results2. MMF method gives optimistic results

1

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ELECTRICAL ENGINEERING

In d.c. shunt motors, the developed torque is

armature current

The speed of a separately excited d.c. motor can be controlled below base speed by (a) armature resistance control and (b) supply voltage control. What happens to the slope of

torque characteristics under

It changes in both types of control It remains unchanged in both types of

It remains unchanged in armature resistance control while changes in supply voltage control It remains unchanged in supply voltage control while changes in armature resistance control

The polarity of interpoles used in d.c.

same as the main pole ahead in generators while opposite of the main pole ahead in motors same as the main pole ahead ion motors while opposite of the main pole ahead in

same as the main pole ahead in both motors and generators opposite of the main pole ahead in both motors and generators

In synchronous generators, examine the following statements about voltage

Synchronous impedance method gives pessimistic results MMF method gives optimistic results






3. In unsaturated machine both methods (synchronous impedance and MMF) give same results.

Which of the statements are correct?(a.) 1, 2 and 3 (b.) Only 1 and 2 (c.) Only 3 (d.) Only 2 and 3

10. Under symmetrical short circuit synchronous generator, the armature reaction is (a.) magnetizing (b.) demagnetizing (c.) cross-magnetising (d.) mainly magnetising

11. In synchronous generators, the fifth harmonic in induced emf can be eliminated by using coils show chorded by an angle(a.) 9o (b.) 18o (c.) 27 o (d.) 36o

12. In induction motor operation, a slip greater than 1 refers to (a.) regenerative braking (b.) motoring in reverse direction(c.) plugging (d.) dynamic braking

13. As the applied voltage to an induction motor, operating under no-load, is reduced to half(a.) its speed reduced and

increases (b.) its speed reduced and stator current also

reduces (c.) its speed reduces but there is not change

in stator current (d.) there is no change in speed but stator

current reduces 14. A 3-phase induction motor is delivering a

load of 10 kW at a lagging p.f. of 0.5. If a 3phase capacitor bank of 7.3 kVAR is connected at its input, the resulting kVA drawn from supply shall be (approximately)(a.) 26.5 (b.) 24.5






In unsaturated machine both methods (synchronous impedance and MMF)

Which of the statements are correct?

Under symmetrical short circuit of a synchronous generator, the armature reaction

In synchronous generators, the fifth harmonic in induced emf can be eliminated by using coils show chorded by an angle

In induction motor operation, a slip greater

motoring in reverse direction

As the applied voltage to an induction motor, load, is reduced to half

its speed reduced and stator current

its speed reduced and stator current also

its speed reduces but there is not change

there is no change in speed but stator

phase induction motor is delivering a ing p.f. of 0.5. If a 3-

capacitor bank of 7.3 kVAR is connected at its input, the resulting kVA drawn from supply shall be (approximately)

(c.) 20.0 (d.) 14.0

15. An electric motor developing a starting torque of 10 Nm starts with a load of 6 Nm at its shaft. If the acceleration at start is 2 rad/sec2 , the moment of inertia of the system must be (a.) 2 kg-m2 (b.) 2 N-m2 (c.) 0.5 kg-m2 (d.) 0.5 N-m2

16. A synchronous motor works as a synchronous condenser if (a.) underexcited (b.) overexcited (c.) excited with 100% excitation(d.) unexcited

17. In relation to damper bar winding in a synchronous motor, examine the following statements: 1. Damper bars are provided in slots on

poles 2. Damper bars improve excitation3. Damper bars help the motor4. Damper bars minimize hunting.

Which of the statements are correct?(a.) 1, 2, 3 (b.) 2, 3 (c.) 1, 4 (d.) 1, 3, 4

18. In large power ratings, synchronous motor is considered superior to induction motor, since (a.) it is less expensive (b.) its efficiency is better(c.) it can be operated at better power f(d.) its speed regulation is superior.

19. An induction motor drive is designed for two speed operation. For this purpose, the motor is provided with two windings on its stator corresponding to 4 poles and 8 poles. While the motor was running on 4 pole winding, a changeover to 8 pole winding is made. The motor will (a.) experience dynamic braking(b.) experience regenerative braking

2





An electric motor developing a starting Nm starts with a load of 6 Nm at

its shaft. If the acceleration at start is 2 , the moment of inertia of the system

A synchronous motor works as a synchronous

excited with 100% excitation

In relation to damper bar winding in a synchronous motor, examine the following

Damper bars are provided in slots on

Damper bars improve excitation Damper bars help the motor self start

minimize hunting. Which of the statements are correct?

In large power ratings, synchronous motor is considered superior to induction motor, since

it is less expensive its efficiency is better it can be operated at better power factor its speed regulation is superior.

An induction motor drive is designed for two For this purpose, the motor

is provided with two windings on its stator corresponding to 4 poles and 8 poles. While the motor was running on 4 pole winding, a changeover to 8 pole winding is made. The

experience dynamic braking nerative braking






(c.) experience no braking but will slow down due to its inertia

(d.) draw dangerously high current20. A d.c. shunt motor drive of 100 h.p. is run (a)

at half the rated speed by armature voltage control and (b) at 1.5 times the rated speed by field control. Its power rating in the two cases shall be modified as (a.) 100 h.p. in both cases (b.) 50 h.p. in case (a) and 150 h.p. in case

(b) (c.) 50 h.p. in case (a) and 100 h.p. in case

(b) (d.) 100 h.p. in case (a) and 150 h.p. in case

(b) 21. A single phase full controlled

work as inverter, if the firing angle is between(a.) 0o and 90o (b.) 60o and 90o (c.) 90o and 180o (d.) 0o and 60o

22. When d.c. voltage is converted to a.c. by an inverter, PWM technique is used to(a.) control only the output voltage from

within the inverter (b.) control both the output voltage and

frequency from within the inverter(c.) control the output current(d.) reduce losses in the inverter

23. A thyristor which is in ON state is to be switched OFF. For this purpose a reverse bias is applied across it. Examine the following statements regarding flow of current from anode to cathode (forward current)1. Forward current can continue to flow if

the circuit is purely resistive 2. Forward current can continue to flow if

the circuit is dominantly inductive3. Forward current can continue to

the circuit is dominantly capacitive4. Forward current will immediately stop

flowing. Which of the above statements are correct?(a.) Only 4 (b.) Only 1






experience no braking but will slow

draw dangerously high current A d.c. shunt motor drive of 100 h.p. is run (a) at half the rated speed by armature voltage control and (b) at 1.5 times the rated speed by

trol. Its power rating in the two cases

50 h.p. in case (a) and 150 h.p. in case



A single phase full controlled rectifier can work as inverter, if the firing angle is between

When d.c. voltage is converted to a.c. by an inverter, PWM technique is used to

control only the output voltage from

oth the output voltage and frequency from within the inverter control the output current reduce losses in the inverter

A thyristor which is in ON state is to be switched OFF. For this purpose a reverse bias is applied across it. Examine the following

ments regarding flow of current from anode to cathode (forward current):

Forward current can continue to flow if the circuit is purely resistive Forward current can continue to flow if the circuit is dominantly inductive Forward current can continue to flow if the circuit is dominantly capacitive Forward current will immediately stop

Which of the above statements are correct?

(c.) Only 2 and 3 (d.) Only 2

24. In a 3-phase full controlled thyristor bridge rectifier operating under continuous conduction mode, each thyristor conducts for (a.) 180o and two thyristors conduct at a time(b.) 120o and three thyristors conduct at a

time (c.) 180o and three thyristors conduct at a

time (d.) 120o and two thyristors conduct at a time

25. A single phase fully controlled rectifier is

feeding a d.c. motor. At voltage is 200 V and motorpm. Neglecting armature resistance and considering continuous conduction, the

armature voltage and speed at (a.) 100 V and 500 rpm(b.) 100 V and 1000 rpm(c.) 200 V and 500 rpm(d.) 100 V and speed will depend upon load

26. The grading capacitors are provided across the series connected interrupters in EHV circuit breakers for (a.) reducing short circuit current (b.) improving power factor(c.) equalizing distribution of recovery

voltage across the interrupters(d.) preventing inductive current chopping.

27. The minimum cost operating condition for a thermal plant is that (a.) the larger units should gener

power as compared to smaller units(b.) the smaller units should generate more

power as compared to larger units(c.) the incremental cost rate of the units be

proportional to their rating(d.) the incremental cost rate of all the units

be equal 28. The effect of earth on a three

transmission line is to(a.) increase its capacitance and decrease

inductance (b.) decrease its capacitance and increase

inductance

3





phase full controlled thyristor bridge rectifier operating under continuous conduction mode, each thyristor conducts for

and two thyristors conduct at a time and three thyristors conduct at a

and three thyristors conduct at a

and two thyristors conduct at a time A single phase fully controlled rectifier is

feeding a d.c. motor. At α = 0o, the armature voltage is 200 V and motor speed is 1000 rpm. Neglecting armature resistance and considering continuous conduction, the

armature voltage and speed at α = 60o will be 100 V and 500 rpm 100 V and 1000 rpm 200 V and 500 rpm 100 V and speed will depend upon load

The grading capacitors are provided across the series connected interrupters in EHV

reducing short circuit current improving power factor equalizing distribution of recovery voltage across the interrupters preventing inductive current chopping.

The minimum cost operating condition for a

the larger units should generate more power as compared to smaller units the smaller units should generate more power as compared to larger units the incremental cost rate of the units be proportional to their rating the incremental cost rate of all the units

rth on a three-phase transmission line is to

increase its capacitance and decrease

decrease its capacitance and increase






(c.) increase its capacitance without affecting inductance

(d.) increase its inductance without affecting capacitance.

29. In case of a transmission line if the voltage regulation is negative, then the load power factor is (a.) zero (b.) lagging (c.) unity (d.) leading

30. The voltage gradient at the surface of a cable, having a conductor of radius r and a sheath of radius R, is minimum when(a.) R = r/e (b.) R = r (c.) R =er (d.) R = er

where e = natural exponent 31. In an N-bus power system with M

the size of the Jacobian matrix for load flow calculation is (a.) N×N (b.) (N-M) ×(N-M) (c.) (N-1) × (N-1) (d.) (N-M-1) × (N-M-1)

32. The zero-sequence equivalent circuit of a delta-star transformer, with solidly grounded neutral, is

(a.)

(b.)

(c.)

(d.) 33. The plug setting multiplier of a 5 Amp.

IDMT relay for a fault current of 4000 Amp. and a relay setting of 125%, with a C.T. ratio of 80 will be (a.) 1 (b.) 2 (c.) 4






increase its capacitance without affecting

increase its inductance without affecting

ase of a transmission line if the voltage regulation is negative, then the load power

The voltage gradient at the surface of a cable, having a conductor of radius r and a sheath of radius R, is minimum when

bus power system with M-PV buses,

the size of the Jacobian matrix for load flow

sequence equivalent circuit of a transformer, with solidly grounded

etting multiplier of a 5 Amp. IDMT relay for a fault current of 4000 Amp. and a relay setting of 125%, with a C.T. ratio

(d.) 8 34. If the cost of electricity generation is to be

reduced then (a.) the diversity factor and load factor both

should be low (b.) the diversity factor and load factor both

should be high (c.) the diversity factor should be high while

the load factor should be low(d.) the diversity factor should be low and

the load factor should be high35. The coefficients of reflection for voltage and

current for an open ended line are respectively (a.) -1.0 and -1.0 (b.) -1.0 and 1.0 (c.) 1.0 and 1.0 (d.) 1.0 and -1.0

36. If G is the MVA rating of a synchronous machine with inertia constant H sec. and operating frequency f, then the angular momentum M of the machine, in MJsec/electrical degree, is

(a.) 180

GH

f

(b.) 360

GH

f

(c.) GH

f

(d.) 180

H

f

37. Circular grooves are provided underneath the insulator disc for (a.) reducing the weight of the disc(b.) improving disc strength(c.) increasing cooling of the disc(d.) increasing the creepage distance

38. The arc formation in vacuum circuit bris initiated by (a.) field emission (b.) thermal emission(c.) photo emission (d.) secondary emission

4





If the cost of electricity generation is to be

the diversity factor and load factor both

the diversity factor and load factor both

the diversity factor should be high while the load factor should be low the diversity factor should be low and

should be high The coefficients of reflection for voltage and current for an open ended line are

If G is the MVA rating of a synchronous machine with inertia constant H sec. and operating frequency f, then the angular momentum M of the machine, in MJ-sec/electrical degree, is

Circular grooves are provided underneath the

reducing the weight of the disc improving disc strength increasing cooling of the disc increasing the creepage distance

The arc formation in vacuum circuit breaker

thermal emission

secondary emission






39. The series reactors are used to (a.) limit over voltages (b.) control Ferranti effect (c.) limit fault current (d.) improve stability

40. If the spacings Dab, Dbc and Dphases a, b, and c of a three phase transmission line are not equal, then the equivalent spacing Deq can be calculated as (a.) (Dab + Dbc + Dca)/3 (b.) (Dab * Dbc * Dca)/3 (c.) (Dab + Dbc + Dca)

1/3 (d.) (Dab * Dbc * Dca)

1/3 41. For calculating fault current for a d

to ground fault in an ungrounded system(a.) positive, negative and zero sequence

networks are connected in series (b.) positive, negative and zero sequence

networks are connected in parallel(c.) positive and negative sequence networks

are connected in parallel(d.) positive and negative sequence networks

are connected in series 42. The unit of R, the regulation constant of

turbine speed governor, is (a.) Hz/MW (b.) MW/sec (c.) MW/Hz (d.) MW-Hz

43. If in a power system the line to line base voltage is VB kV and the 3is SB, then the base impedance of the system is

(a.) 2

3B

B

V

SΩ

(b.) 23 B

B

V

SΩ

(c.) 2

B

B

V

SΩ

(d.) 2 *1000B

B

V

SΩ

44. The pumped storage hydro plants are used as






The series reactors are used to

and Dca between the phases a, b, and c of a three phase transmission line are not equal, then the

can be calculated as

For calculating fault current for a double line to ground fault in an ungrounded system

positive, negative and zero sequence networks are connected in series positive, negative and zero sequence networks are connected in parallel positive and negative sequence networks

lel positive and negative sequence networks are connected in series

The unit of R, the regulation constant of

If in a power system the line to line base kV and the 3-phase base MVA

then the base impedance of the system

The pumped storage hydro plants are used as

(a.) Base load plants (b.) Peak load plants(c.) Mid-range plants(d.) both (A) and (B)

45. The specified operating criteria for the proper operation of interconnected power system is , that Area Control Error (ACE) must be zero at least once in a (a.) 1 sec period (b.) 1 min period (c.) 10 min period (d.) 1 hr period

46. If a network has b branches and n nodes,the number of independent KVL equations for the network are (a.) b-n (b.) n-b+1 (c.) b-n-1 (d.) b-n+1

47. What will be the value of Zpower transfer condition in the circuit shown in Fig. Q.47?

(a.) (2-j2)Ω

(b.) (2+j2)Ω

(c.) (3-j2)Ω

(d.) (3+j2)Ω 48. Which of the following statements

apply to series RLC circuit?(a.) The current and the admittance are

maximum at resonance(b.) The phase angle of the impedance

changes from +90frequency is varied from 0 to

(c.) The total stored energy in the circuit is constant at resonance

(d.) The power factor is unity at resonance49. The average value of a sine wave over a full

cycle is

5





Base load plants

range plants and (B)

The specified operating criteria for the proper operation of interconnected power system is ,

Area Control Error (ACE) must be zero

If a network has b branches and n nodes, then the number of independent KVL equations

What will be the value of ZL for maximum power transfer condition in the circuit shown

Which of the following statements does not apply to series RLC circuit?

The current and the admittance are maximum at resonance The phase angle of the impedance changes from +90o to –90o as the frequency is varied from 0 to ∞ The total stored energy in the circuit is constant at resonance The power factor is unity at resonance

The average value of a sine wave over a full






(a.) max2V

π

(b.) max

2

V

(c.) maxV

π

(d.) zero 50. A two port network is reciprocal and

symmetrical, if ABCD parameters conditions: (a.) AB-CD = 1 and A = D(b.) AD-BC = 1 and A = D(c.) AC-BD = 1 and A = D(d.) AD-BC = 1 and B = C

51. Tellegen’s theorem is applicable to(a.) linear time invariant networks only(b.) non-linear time invariant network only(c.) any network satisfying Kirchoff’s

current and voltage laws(d.) linear time variant network only

52. The circuit element having identical properties for forward and reverse direction of current flow through it, is called a(a.) linear element (b.) irreversible element (c.) bilateral element (d.) unilateral element

53. A fundamental cut set contains(a.) only one tree branch and minimum

number of links (b.) only one link and minimum number of

tree branches (c.) only tree branches (d.) only links

54. In the circuit shown in Fig. Q. 54 if the switch is opened at t = 0 and the initial current through the switch and Lthen the current i(t) and the voltage v(t) o0 are






A two port network is reciprocal and symmetrical, if ABCD parameters satisfy the

CD = 1 and A = D BC = 1 and A = D BD = 1 and A = D

Tellegen’s theorem is applicable to

linear time invariant networks only linear time invariant network only

any network satisfying Kirchoff’s and voltage laws

linear time variant network only The circuit element having identical properties for forward and reverse direction of current flow through it, is called a

tal cut set contains only one tree branch and minimum

only one link and minimum number of

In the circuit shown in Fig. Q. 54 if the switch is opened at t = 0 and the initial

witch and L1 is 10 A, then the current i(t) and the voltage v(t) of t >

(a.) 0 A, 0 V

(b.) 0 A, ∞ V (c.) 6 A, 12 V (d.) 10 A, 20 V

55. The Thevenin and Norton equivalents of network A at points X, Y (Fig. Q.55) can not be found if

(a.) Networks A and B are coupled(b.) A is an active network(c.) B is a passive network(d.) B is a non-linear network

56. If X ⋅Y= 0 then X⊕Y is equal to (a.) X+Y

(b.) X+Y

(c.) X Y+X Y⋅ ⋅ (d.) 1

57. The value of base x will be (101)x + (110)7 = (101)(a.) 2 (b.) 7 (c.) 8 (d.) 10

58. Consider the counter circuitQ.58.

6





The Thevenin and Norton equivalents of network A at points X, Y (Fig. Q.55) can not

Networks A and B are coupled

active network B is a passive network

linear network

Y is equal to

The value of base x will be = (101)8 + (29)16

Consider the counter circuit shown in Fig.






If the present state QA QB of the counter is Q= 1 & QB = 0, the next state of the counter will be (a.) QA = 1, QB = 1 (b.) QA = 1, QB = 0 (c.) QA = 0, QB = 1 (d.) QA = 0, QB = 0

59. In 8085 A µp, stack pointer is a 16 bit register which is (a.) Incremented by 2 whenever data is

pushed on to stack (b.) Incremented by 2 whenever data is

popped from stack (c.) Incremented by 1 whenever data is

pushed on the stack (d.) Neither incremented nor decremented a

result of PUSH and POP operation60. The instruction LDA 0805H is used to inp

data from an I/O device. Choose the correct statement (a.) It is possible only if device is interfaced

using memory mapped I/O(b.) It is possible only if device is interfaced

using I/O mapped I/O (c.) Instead of LDA 0805H, the instruction

STA 0805H should be used(d.) only IN PORT instruction can be used in

8085 A µp. 61. The macro RTL implemented by INR M in

8085 A microprocessor is

(a.) (M)← (M) +1

(b.) (H,L)←(H,L) + 1

(c.) M(H,L) ←M(H,L) +1

(d.) (H) ← (H) + 1, (L) ← 62. In an 8085 A microprocessor when INTR

interrupt, becomes active, thtransferred to (a.) 0024 H memory location(b.) 003C H memory location(c.) anywhere in the memory decided by the

interrupting device (d.) 0034 H memory location

63. In an 8255 programmable peripheral interface both the groups are programmed in made ‘0’.






of the counter is QA = 0, the next state of the counter will

p, stack pointer is a 16 bit register

2 whenever data is

Incremented by 2 whenever data is

Incremented by 1 whenever data is

Neither incremented nor decremented a result of PUSH and POP operation

The instruction LDA 0805H is used to input a data from an I/O device. Choose the correct

It is possible only if device is interfaced using memory mapped I/O It is possible only if device is interfaced

Instead of LDA 0805H, the instruction STA 0805H should be used only IN PORT instruction can be used in

The macro RTL implemented by INR M in

(L) +1 In an 8085 A microprocessor when INTR interrupt, becomes active, the control will be

0024 H memory location 003C H memory location anywhere in the memory decided by the

0034 H memory location In an 8255 programmable peripheral interface both the groups are programmed in made ‘0’.

The possible number of combination in which the ports can be programmed is(a.) 16 (b.) 4 (c.) 3 (d.) 2

64. The meaning of direct addressing mode is(a.) The address of operand is available in

register pair (b.) The address of operand is available in

PC (c.) The data is directly available in the

instruction itself (d.) The address of the operand is available

in the instruction itself. 65. The schematic symbol shown in following

Fig. Q. 65 is that of

(a.) Zener diode (b.) Esaki diode (c.) Varistor (d.) Varactor

66. The V-I characteristic shown in Fig. Q. 66 is that of

(a.) PN junction diode(b.) Tunnel diode (c.) Zener diode (d.) Varactor

67. In a four variable Vsimplified expression for X is

7





possible number of combination in which the ports can be programmed is

The meaning of direct addressing mode is The address of operand is available in

The address of operand is available in

The data is directly available in the struction itself

The address of the operand is available in the instruction itself.

The schematic symbol shown in following

I characteristic shown in Fig. Q. 66 is

junction diode

In a four variable V-K Map shown in Fig. simplified expression for X is






(a.) AB+ CD

(b.) A B+ C D⋅ ⋅

(c.) B D⋅ (d.) A D + B C⋅ ⋅

68. In following circuit assuming voltage drop of LED as 2 V, the LED current when transistor is saturated will be

(a.) 12 mA (b.) 9.7 mA (c.) 6 mA (d.) 5.8 mA

69. In the following circuit the collector voltage VC is (assume VBE = 0.7 V)

(a.) -17.4 V (b.) 5.6 V (c.) 12.3 V (d.) 17.4 V

70. From the following V-K map the simplified expression for Z is

(a.) ABC ABC+

(b.) ABC ABC+

(c.) B






assuming voltage drop of LED as 2 V, the LED current when transistor

In the following circuit the collector voltage

K map the simplified

(d.) ABC ABC ABC ABC+ + +71. The method of absolute measurement of

resistance is (a.) Ohm method (b.) Potentiometer method(c.) Lorenz method (d.) Rayleigh method

72. The instrument which gives the value of the quantity to be measured in terms of instrument constants and its deflection is called the (a.) absolute instrument(b.) secondary instrument(c.) recording instrument(d.) integrating instrument

73. The current passing through a resistor of

(50±0.2)Ω is (4.0±0.02)A. in the computed value of power will be(a.) 0.2 % (b.) 0.4 % (c.) 0.9 % (d.) 1.4 %

74. The coil of an instrument has 40 turns. The mean length of the coil is 25 mm and the axial length of the coil is 20 mm. If the flux density is 0.1 T and the coil current is 20 mA, the torque on the moving coil will be (a.) 40×10–6 N-m (b.) 20×10–6 N-m (c.) 40×10–3 N-m (d.) 20×10–3 N-m

75. In thermocouple element, heat energy transferred to the hot junction is converted to electrical energy by (a.) Johnson’s effect (b.) Seebeck effect (c.) Hall effect (d.) Faraday’s effect

76. The scale of dynamometer type instrument marked in terms of RMS value would b(a.) uniform throughout (b.) non-uniform, crowded near full scale(c.) non-uniform, crowded at the beginning(d.) non-uniform, crowded around mid

8





ABC ABC ABC ABC+ + + The method of absolute measurement of

Potentiometer method

Rayleigh method The instrument which gives the value of the quantity to be measured in terms of instrument constants and its deflection is

absolute instrument secondary instrument recording instrument integrating instrument current passing through a resistor of

0.02)A. The limiting error in the computed value of power will be

The coil of an instrument has 40 turns. The mean length of the coil is 25 mm and the axial length of the coil is 20 mm. If the flux density is 0.1 T and the coil current is 20 mA, the torque on the moving coil will be

In thermocouple element, heat energy transferred to the hot junction is converted to

The scale of dynamometer type instrument marked in terms of RMS value would be

uniform throughout uniform, crowded near full scale uniform, crowded at the beginning uniform, crowded around mid-scale






77. The harmonic distortion percentage is accurately measure with (a.) V.T.V.M. (b.) An oscilloscope (c.) Harmonic distortion meter(d.) Square wave generator

78. A thermometer has a time constant of 3.5 s. It is quickly taken from a temperaturewater bath at 100oC. What temperature be indicated after 1.5 s? (a.) 100oC (b.) 50oC (c.) 35oC (d.) 15oC

79. A digital voltmeter employerequires a start pulse, uses an analog comparator and has a relatively fixed conversion time independent of applied voltage. The ADC is (a.) digital ramp converter (b.) dual slope converter (c.) successive approximation converter(d.) flash type

80. In measurements made using Qimpedance elements should be connected in (a.) star (b.) delta (c.) series (d.) parallel

81. The measured values of iron losses of a magnetic specimen are 15 W and 25 W at, 40 Hz and 60 Hz respectively at constant flux density. The respective hysteresis acurrent losses at 50 Hz are (a.) 14.584 W and 5.208 W(b.) 7.5 W and 12.5 W (c.) 5.208 W and 14.548 W(d.) 5 W and 10 W

82. The most common and best bridge method for precise measurement of inductance over a wise range is (a.) Maxwell’s (b.) Hay’s (c.) Wien (d.) Anderson






The harmonic distortion percentage is

Harmonic distortion meter wave generator

A thermometer has a time constant of 3.5 s. It is quickly taken from a temperature 0oC to

C. What temperature will

ees an ADC which requires a start pulse, uses an analog comparator and has a relatively fixed conversion time independent of applied

successive approximation converter

ts made using Q-meter, impedance elements should be connected in

The measured values of iron losses of a magnetic specimen are 15 W and 25 W at, 40 Hz and 60 Hz respectively at constant flux density. The respective hysteresis and eddy

14.584 W and 5.208 W

5.208 W and 14.548 W

The most common and best bridge method for precise measurement of inductance over a

83. The AC bridge that can be used for accurate determination of excitation frequency is (a.) Wien bridge (b.) Schering bridge (c.) Anderson bridge(d.) De Sauty bridge

84. A thermo-couple arrangement is to be used to measure temperature in the range of 700800oC. Point out the pair thsuitable for this application(a.) Copper-constantan(b.) Chromel-alumel(c.) Platinum-platinum rhodium(d.) Iron-constantan

85. Rotameter is employed for measuring(a.) flow (b.) rotation (c.) specific gravity (d.) viscosity

86. Consider the following statements regarding the stability of a control system1. Gain margin and phase margin are

negative 2. Gain margin and phase margin are

positive 3. All roots of characteristic equation must

lie in left half of s4. Gain margin is positive and phase

margin is negativeOut of these statements(a.) 1 and 3 are correct(b.) 1 and 2 correct (c.) 2 and 3 are correct(d.) 3 and 4 are correct

87. In the feedback system shown below, if the steady state error for a step input is 0.05, then the value of K is

(a.) 0.05 (b.) 0.95 (c.) 1.9

9





AC bridge that can be used for accurate determination of excitation frequency is

Anderson bridge

couple arrangement is to be used to

measure temperature in the range of 700-Point out the pair that would be most

suitable for this application constantan

alumel platinum rhodium

Rotameter is employed for measuring

Consider the following statements regarding of a control system

Gain margin and phase margin are

Gain margin and phase margin are

All roots of characteristic equation must lie in left half of s-plane Gain margin is positive and phase margin is negative

Out of these statements and 3 are correct

2 and 3 are correct 3 and 4 are correct

In the feedback system shown below, if the steady state error for a step input is 0.05, then






(d.) 19 88. Match List I with List II and select the correct

answer using the codes given below the lists:List I (Location of poles on s

A.

B.

C.

D. List II (Impulse Response)

1.

2.

3.

4. Codes: A B (a.) 4 1 (b.) 3 4 (c.) 1 3 (d.) 1 3

89. The Nyquist plot for a control system is shown in Fig. Q.89. The Bode the same system will be






Match List I with List II and select the correct answer using the codes given below the lists:

(Location of poles on s-plane)

List II (Impulse Response)

C D 2 3 2 1 2 4 4 2

The Nyquist plot for a control system is shown in Fig. Q.89. The Bode plot of |G| for

(a.)

(b.)

(c.)

(d.) 90. A unity feedback second order control system

is characterized by G s

where J = moment of inertiaB = viscous damping coefficientK = system gain

The transient response specification which is not affected by variation of system gain is the (a.) peak overshoot (b.) damped frequency of oscillations(c.) setting time (d.) rise time

10





A unity feedback second order control system

( ) ( )K

G ss Js B

=+

J = moment of inertia B = viscous damping coefficient

The transient response specification which is not affected by variation of system gain is the

damped frequency of oscillations






91. The second order system X = AX has

1 1

1 0A

− − =

. The value of its damping

factor ξ and natural frequency respectively (a.) 0.5 and 1 (b.) 1 and 1 (c.) 0.707 and 2 (d.) 1 and 2

92. A negative unit feedback system has forward path transfer function as Ks/(sbreak in point(s) of root locus occur at(a.) s=5 (b.) s=-5 (c.) both A & B (d.) s = 25

93. In an electrical analog of mechanical system of rotational motion, using torqueanalogy, inertial and viscous damper are respectively analogous to (a.) Inductance and capacitance(b.) Capacitance and resistance (c.) Inductance and resistance(d.) Capacitance and inductance

94. The characteristic equation of a feedback system is given by

4 3 26 11 6 04

Ks s s s− + + + =

For this system, stable closed loop behavior can be ensured when gain K is such that

(a.) 0 ≤ K ≤ 40

(b.) 0 ≤ K ≤ 10

(c.) 0 ≤ K ≤ ∞

(d.) 0 ≤ K ≤ 20

95. The eigen values of the matrix

(a.) (a+1), 0 (b.) a, 0 (c.) (a-1), (a-1) (d.) 0, 0

96. A first order linear system is initially relaxed. For a unit step signal u(t), the response of the system is






The second order system X = AX has

. The value of its damping

and natural frequency ωn are

A negative unit feedback system has forward path transfer function as Ks/(s2+2s+25). The break in point(s) of root locus occur at

In an electrical analog of mechanical system of rotational motion, using torque-voltage analogy, inertial and viscous damper are

Inductance and capacitance Capacitance and resistance Inductance and resistance

apacitance and inductance The characteristic equation of a feedback

6 11 6 0− + + + =

For this system, stable closed loop behavior can be ensured when gain K is such that

values of the matrix 1

1

a

a

are

A first order linear system is initially relaxed. For a unit step signal u(t), the response of the

(1-e-3t), t > 0

If a signal 3. u(t) + δ(t) is applied to the same initially relaxed system, the response will be

(a.) 3(1-e-3t) .u(t)+ e-

(b.) (1-3e-3t) .u(t) (c.) 3(1+e-3t) .u(t) (d.) 3.u(t)

97. Consider the following statements regarding the non linear system1. dead zone can be classified as single

valued non-linearity2. hysteresis and backlash can be classified

as double valued non3. Coulomb friction can be classified as

double valued nonOut of these statements(a.) 1 and 3 are correct(b.) all three are correct(c.) 1 and 2 are correct(d.) 2 and 3 are corre

98. Consider the system

( ) ( )1 1

0 1X t X t U t

= +

( ) 1 2[ ] ( )C t d d X t= .

The condition for complete state controllability and complete observability is(a.) d1 > 0, b2 > 0, b1

(b.) d1 > 0, d2 > 0, b1

(c.) b1 > 0, b2 > 0, d1

(d.) b1 > 0, b2 > 0, anything

99. The semilog plot of gain characteristic (BODE plot) of a network is shown in the Fig. Q.99.

The gain cross over frequency(a.) 20 rad/sec

11





(t) is applied to the same initially relaxed system, the response will be

3t. δ(t)

Consider the following statements regarding the non linear system

dead zone can be classified as single linearity

hysteresis and backlash can be classified as double valued non-linearity Coulomb friction can be classified as double valued non-linearity

Out of these statements 1 and 3 are correct all three are correct 1 and 2 are correct 2 and 3 are correct

1

2

( )b

X t X t U tb

= +

[ ] ( )C t d d X t .

The condition for complete state controllability and complete observability is

1 and d2 can be anything

1 and b2 can be anything

1 and d2 can be anything > 0, d1 < 0 and d2 can be

The semilog plot of gain characteristic (BODE plot) of a network is shown in the

frequency ωc is






(b.) 30 rad/sec (c.) 40 rad/sec (d.) 25 rad/sec

100. The pole-zero configuration of a phase lead compensating network is given by

(a.)

(b.)






zero configuration of a phase lead compensating network is given by

(c.)

(d.)

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