Q-sample Papers for Rites

7/29/2019 Q-sample Papers for Rites

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Q.1 The two windings of a transformer is(A) conductively linked.(B) inductively linked.(C) not linked at all.(D) electrically linked.

Ans : B

Q.2 A salient pole synchronous motor is running at no load. Its field current is switched off. The motor will(A) come to stop.(B) continue to run at synchronous speed.(C) continue to run at a speed slightly more than the synchronous speed.(D) continue to run at a speed slightly less than the synchronous speed.Ans: B

Q.3 The d.c. series motor should always be started with load because(A) at no load, it will rotate at dangerously high speed.

(B) it will fail to start.(C) it will not develop high starting torque.(D) all are true.Ans: A

Q.4 The frequency of the rotor current in a 3 phase 50 Hz, 4 pole induction motor at full load speed isabout(A) 50 Hz.(B) 20 Hz.(C) 2 Hz.(D) Zero.Ans: C

Q.5 In a stepper motor the angular displacement(A) can be precisely controlled.(B) it cannot be readily interfaced with micro computer based controller.(C) the angular displacement cannot be precisely controlled.(D) it cannot be used for positioning of work tables and tools in NC machines.Ans: A

Q.6 The power factor of a squirrel cage induction motor is(A) low at light load only.(B) low at heavy load only.(C) low at light and heavy load both.(D) low at rated load only.Ans: A

Q.7 The generation voltage is usually(A) between 11 KV and 33 KV.(B) between 132 KV and 400 KV.(C) between 400 KV and 700 KV.


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(D) None of the above.Ans: A

Q.8 When a synchronous motor is running at synchronous speed, the damper winding produces(A) damping torque.

(B) eddy current torque.(C) torque aiding the developed torque.(D) no torque.Ans: D

Q.9 If a transformer primary is energised from a square wave voltage source, its output voltage will be(A) A square wave.(B) A sine wave.(C) A triangular wave.(D) A pulse wave.Ans: A

Q.10 In a d.c. series motor the electromagnetic torque developed is proportional toOption figureAns: BQ.11 In a 3phase induction motor running at slip s the mechanical power developed in terms of air gappower11 and 12 figureIn a 3 phase induction motor the maximum torque(A) is proportional to rotor resistance(B) does not depend on(C) is proportional to(D) is proportional to

Q.13In a d.c. machine, the armature mmf is(A) stationary w.r.t. armature.(B) rotating w.r.t. field.(C) stationary w.r.t. field.(D) rotating w.r.t. brushes.Ans: C

Q.14In a transformer the voltage regulation will be zero when it operates at(A) unity p.f.(B) leading p.f.(C) lagging p.f.(D) zero p.f. leading.Ans: B

Q.15 The maximum power in cylindrical and salient pole machines is obtained respectively at load anglesof

Q.16 The primary winding of a 220/6 V, 50 Hz transformer is energised from 110 V, 60 Hz supply. The


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secondary output voltage will be(A) 3.6 V.(B) 2.5 V.(C) 3.0 V.(D) 6.0 V.

Ans: C

Q.17 The emf induced in the primary of a transformer(A) is in phase with the flux.(B) lags behind the flux by 90 degree.(C) leads the flux by 90 degree.(D) is in phase opposition to that of flux.Ans: C

Q.18 The relative speed between the magnetic fields of stator and rotor under steady state operation iszero for a

(A) dc machine.(B) 3 phase induction machine.(C) synchronous machine.(D) single phase induction machine.Ans: all options are correct

Q.19 The current from the stator of an alternator is taken out to the external load circuit through(A) slip rings.(B) commutator segments.(C) solid connections.(D) carbon brushes.Ans: C

Q.20 A motor which can conveniently be operated at lagging as well as leading power factors is the(A) squirrel cage induction motor.(B) wound rotor induction motor.(C) synchronous motor.(D) DC shunt motor.Ans: C

Q.21 A hysteresis motor(A) is not a self-starting motor.(B) is a constant speed motor.(C) needs dc excitation.(D) can not be run in reverse speed.Ans: B

Q.22The most suitable servomotor for low power applications is(A) a dc series motor.


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(B) a dc shunt motor.(C) an ac two-phase induction motor.(D) an ac series motor.Ans: B

Q.23 The size of a conductor used in power cables depends on the(A) operating voltage.(B) power factor.(C) current to be carried.(D) type of insulation used.Ans: C

Q.24 Out of the following methods of heating the one which is independent of supply frequency is(A) electric arc heating(B) induction heating(C) electric resistance heating

(D) dielectric heatingAns: CQ.25

A two-winding single phase transformer has a voltage regulation of 4.5% at full-load and unity power-factor.At full-load and 0.80 power-factor lagging load the voltage regulation will be(A) 4.5%.(B) less than 4.5%.(C) more than 4.5%.(D) 4.5% or more than 4.5%.Ans: C

Electronics Quiz

1. In a mercury arc rectifier

Ion stream moves from cathode to anode

Current flows from cathode to anode

Electron stream moves form anode to cathode

Ion stream moves from anode to cathode

.The answer is Ion stream moves from anode to cathode

2. For producing cathode spot in a mercury arc rectifier

An auxiliary electrode is used


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Tube is evacuated

Low mercury vapour pressures are used

Anode is heated-Answer

.3. If the voltage of anode B is raised to 510 V

Anode B will conduct but anode A will also continue to conduct

Anode B will not conduct but anode A will continue to conduct-Answer

Both anodes will not conduct

None of these

.4. Ripple frequency of full wave rectifier working on 50 Hz supply will be

25 Hz-Answer

150 Hz

6 anode rectifier with inter phase transformer

All will have identical power factor

.5. The form factor for half-wave rectifier sine wave is

1.05

1.15

1.45

1.57-Answer

6. A silicon controlled rectifier is a

Unijuction device

Device with three junctions-Answer

Device with four junctions


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None of the above

.7. For full-wave rectifier sine wave, form factor is

1.55

1.44

1.22

1.11-Answer

.8. At absolute zero temperature a semi-conductor behaves as

An Insulator-Answer

A Super-Conductor

A Good Conductor

A Variable Resistor

.9. An electron in the conduction band

Has higher energy than the electron in the valence band-Answer

Has lower energy than the electron in the valence band

Loses its charge easily

Jumps to the top of the crystal

.10. EG for silicon is 1.12 eV and for germanium is 0.72 eV thus it can be conducted that

More number of electron-hole pairs will be generated in silicon than in germanium at room temperature

Less number of electron hole pairs will be generated in silicon than in germanium at room temperature-Answer

Equal number of electron hole pairs will be generated in both at lower temperatures

Equal number of electron hole pairs will be generated in both at higher temperatures


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.11. Before doping semiconductor material is generally

Dehydrated

Heated

Hardened

Purified-Answer

.12. Select the one that is a acceptor impurity element

Antimony

Gallium-Answer

Arsenic

Phosphorous

.13. At room temperature when a voltage is applied to an intrinsic semiconductor

Most of the electrons and holes move towards negative terminal

Most of the electrons and holes move towards positive terminal

Electrons move towards positive terminal and holes towards negative terminal-Answer

Electrons move towards negative terminal and holes towards positive terminal

.14. Under which of the following conditions avalanche breakdown in a semiconductor diode takes place?

When potential barrier is reduced to zero

When reverse bias exceeds a certain value-Answer

When forward bias exceeds a certain value

When forward current exceeds a certain value

.


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15. Select the rectifier that needs four diodes

Half wave rectifier

Center-tap full wave rectifier

Bridge rectifier-Answer

None of the above

.16. Maximum forward current in case of signal diode is in the range of

1A to 10A

0.1A to 1A

Few milli amperes-Answer

Few nano amperes

.17. In a semiconductor avalanche breakdown takes place when

Reverse bias exceeds the limiting value-Answer

Forward bias exceeds the limiting value

Forward current exceeds the limiting value

Potential barrier is reduced to zero

.18. The D.C output voltage from a power supply

Increases with higher values of filter capacitance and decreases with more load current-Answer

Decreases with higher values of filter capacitance and increases with more load current

Decreases with higher values of filter capacitance as well as with more load current

Increases with higher values of filter capacitance as well as with more load current

.19. A solar cell provides a example of

Photo Voltaic Cell-Answer


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Photo Conductive Cell

Photo Emissive Cell

Photo Radiation Cell

.20. When yellow light is incident on a surface, no electrons are emitted while green light can emit. If redlight is incident on the surface, then it is expected that

No electrons are emitted-Answer

Hotons are emitted

Electrons of higher energy are emitted

Electrons of lower energy are emitted

.21. An ideal diode should have

Zero resistance in the forward bias as well as reverse bias

Zero resistance in the forward bias and an infinitely large resistance in reverse bais-Answer

Infinitely large resistance in reverse bias

Infinitely large resistance in forward as well as reverse bais

.22. The reverse resistance of a PN juction diode

Is always low

Is always high

Is given by breakdown voltage / reverse leakage current-Answer

Is given by forward voltage / reverse leakage current

.23. In which case the temperature coefficient is positive

Intrinsic Semi-Conductor

Extrinsic Semi-Conductor-Answer


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Both intrinsic as well as extrinsic semi-conductor

Neither intrinsic nor extrinsic semi-conductor

.24. A PNP transistor is generally made of

Silicon

Germanium

Either silicon or germanium-Answer

None of the above

.25. In a transistor the region that is very lightly doped and is very thin is

Emitter

Base-Answer

Collector

None of these

.26. In a NPN transitor, when emitter junction is forward biased and collector junction is reverse biased,the transistor will operate in

Active Region-Answer

Saturated Region

Cut of Region

Inverted Region

.27. A transistor will operate in inverted region if

Emitter junction is forward biased and collector junction is reverse biased

Emitter junction is reverse biased and collector junction is forward biased-Answer

Emitter junction as well as collector junction are forward biased


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Emitter junction as well as collector junction are reverse biased

.28. Which of the following is essential for transistor action ?

The base region must be very wide

The base region must be very narrow-Answer

The base region must be made of some insulating material

The collector region must be heavily doped

.29. In a transistor, current ICBO flows when

Some D.C voltage is applied in the reverse direction to the emitter junction with the collector open circuited

Some D.C voltage is applied in the forward direction to the collector junction with the emitter open circuited

Some D.C voltage is applied in the reverse direction to the collector junction with the emitter open circuited-Answer

Some D.C voltage is applied in the forward direction to the emitter junction with the collector open circuited

.30. The current Icbo

Increases with increase in temperature-Answer

Is normally greater for silicon transistors than germanium transistors

Mainly depends on the emitter base junction

Depends largely on the emitter doping

.31. Thermal runway of a transitor occurs when

Heat dissipation from transistor is excessive

Transistor joints melt due to high temperature

There is excessive leakage current due to temperature rise-Answer

None of above


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.

1 The problems 3-SAT and 2-SAT areA) both in P

B) both NP-completeC) NP-complete and in P respectivelyD) undecidable and NP-complete respectivelyAnswer : (C)

2 Consider the following relation schema pertaining to a students database: Student (rollno, name,address) Enroll (rollno, courseno, coursename)where the primary keys are shown underlined. The number of tuples in the Student and Enroll tables are120 and 8 respectively. What are the maximum and minimum number of tuples that can be present in(Student * Enroll), where *denotes natural join?A) 8, 8

B) 120, 8C) 960, 8D) 960, 120Answer : (C)

3 Consider a relation scheme R = (A, B, C, D, E, H) on which the following functional dependencies hold :(A -> B, BC -> D, E -> C, D -> A). What are the candidate keys of R?A) AE, BEB) AE, BE, DEC) AEH, BEH, BCHD) AEH, BEH, DEH

Answer : (D)

4 The goal of structured programming is toA) have well indented programsB) be able to infer the flow of control from the compiled codeC) be able to infer the flow of control from the program textD) avoid the use of GOTO statementsAnswer : (C)

5 The tightest lower bound on the number of comparisons, in the worst ease, for comparison-based sortingis of the order of

A) nB) n 2C) n log nD) n log2 nAnswer : (B)

6 A circuit outputs a digit in the form of 4 bits. 0 is represented by 0000,1 by 0001,..., 9 by 1001. Acombinational circuit is to be designed which takes these 4 bits as input and outputs 1 if the digit 5, and 0


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otherwise. If only AND, OR and NOT gates may be used, what is the minimum number of gates requiredA) 2B) 3C) 4D) 5

Answer : (C)

7 WA and B are the only two stations on an Ethernet. Each has a steady queue of frames to send. Both Aand B attempt to transmit a frame, collide, and A wins the first backoff race. At the end of this successfultransmission by A, both A and B attempt to transmit and collide. The probability that A wins the secondbackoff race isA) 0.5B) 0.625C) 0.75D) 1.0Answer : (A)

8 If 73x (in base-x number system) is equal to 54y (in base-y number system), the possible values of x andy areA) 8, 16B) 10, 12C) 9, 13D) 8, 11Answer : (D)

9 In a packet switching network, packets are routed from source to destination along a single path havingtwo intermediate nodes. If the message size is 24 bytes and each packet contains a header of 3 bytes, thenthe optimum packet size isA) 4B) 6C) 7D) 9Answer : (D)

10 A Priority-Queue is implemented as a Max-Heap. Initially, it has 5 elements. The level-order traversal ofthe heap is given below: 10, 8,5,3,2 Two new elements 1 and 7 are inserted in the heap in that order. Thelevel-order traversal of the heap after the insertion of the elements isA) 10,8,7,5,3,2,1B) 10,8,7,2,3,1,5C) 10,8,7,1,2,3,5D) 10,8,7,3,2,1,5Answer : (D)

11 Consider an operating system capable of loading and executing a single sequential user process at atime. The disk head scheduling algorithm used is First Come First Served (FCFS). If FCFS is replaced byShortest Seek Time First (SSTF), claimed by the vendor to give 50% better benchmark results, what is theexpected improvement in the I/O performance of user programs ?


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A) 50%B) 40%C) 25%br> D) 0%Answer : (D)

12 How many distinct binary search trees can be created out of 4 distinct keys?A) 5B) 14C) 24D) 42Answer : (B)

Q-13 Select the one true statement. A) Every binary tree is either complete or full.B) Every complete binary tree is also a full binary tree.C) Every full binary tree is also a complete binary tree

D) No binary tree is both complete and full.

Q-14 Which data structure has the fastest insertion procedure? A) Binary search treeB) Ordered arrayC) HeapD) Unordered linked listE) Ordered linked list

Q-15 What are the complexities of the insert, remove and search methods of a binary search tree in theworst case? A) insert is O(n), remove is O(n), search is O(n)B) insert is O(log n), remove is O(log n), search is O(n)C) insert is O(log n), remove is O(log n), search is O(log n)D) insert is O(log n), remove is O(log n), search is O(1)E) These methods can't be defined on a binary search tree

Q-16 This Ethernet frame type is characterized by its use of the code AA in the SAP fields. A) Ethernet IIB) Ethernet RAWC) Ethernet 802.2D) Ethernet SNAP

Q-17 Which of the following are examples of routed protocols? (Choose all that apply) A) IPB) IPXC) RIPD) OSPFE) AppleTalk

Q-18 If switches are used to replace hubs on a network, which of the following statements is true? A) Thenumber of broadcast domains will decreaseB) The number of collision domains will increaseC) The number of collision domains will decreaseD) The number of broadcast domains will be zero


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Q-19 Full duplex Ethernet communication is only possible when:

A. Systems are connected to same LAN segmentsB. Systems are connected to a bridged ports

C. Systems are connected to their own switch portD. Systems are running over a fiber optic connection

Q-20 SQL is the combination of

A ) DDL and DQLB ) DDL , DML and DQLC ) DDL,DML,DQL and DCLD ) None of these

Q-21 Which of the following applications may use a stack?

A) A parentheses balancing program.B) Keeping track of local variables at run time.C) Syntax analyzer for a compiler.D) All of the above

Q -22 Consider the implementation of the Stack using a partially-filled array. What goes wrong if we try tostore the top of the Stack at location [0] and the bottom of the Stack at the last used position of the array?

A) Both peek and pop would require linear time.B) Both push and pop would require linear time.C) The Stack could not be used to check balanced parentheses.D) The Stack could not be used to evaluate postfix expressions.

Q-23 Select the one true statement.A) Every binary tree is either complete or full.B) Every complete binary tree is also a full binary tree.C) Every full binary tree is also a complete binary treeD) No binary tree is both complete and full.

Q-24 Which data structure has the fastest insertion procedure? A) Binary search treeB) Ordered arrayC) HeapD) Unordered linked listE) Ordered linked list

Q-25 What are the complexities of the insert, remove and search methods of a binary search tree in theworst case? A) insert is O(n), remove is O(n), search is O(n)B) insert is O(log n), remove is O(log n), search is O(n)C) insert is O(log n), remove is O(log n), search is O(log n)D) insert is O(log n), remove is O(log n), search is O(1)


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E) These methods can't be defined on a binary search tree

Q-26 This Ethernet frame type is characterized by its use of the code AA in the SAP fields.A) Ethernet IIB) Ethernet RAW

C) Ethernet 802.2D) Ethernet SNAP

Q-27 Which of the following are examples of routed protocols? (Choose all that apply) A) IPB) IPXC) RIPD) OSPFE) AppleTalk

Q-28 If switches are used to replace hubs on a network, which of the following statements is true? A) Thenumber of broadcast domains will decrease

B) The number of collision domains will increaseC) The number of collision domains will decreaseD) The number of broadcast domains will be zero

Q-29 Full duplex Ethernet communication is only possible when:

A. Systems are connected to same LAN segmentsB. Systems are connected to a bridged portsC. Systems are connected to their own switch portD. Systems are running over a fiber optic connection

Q-30 SQL is the combination of

A ) DDL and DQLB ) DDL , DML and DQLC ) DDL,DML,DQL and DCLD ) None of these

Q-31 Which of the following applications may use a stack?

A) A parentheses balancing program.B) Keeping track of local variables at run time.C) Syntax analyzer for a compiler.D) All of the above

Q -32 Consider the implementation of the Stack using a partially-filled array. What goes wrong if we try tostore the top of the Stack at location [0] and the bottom of the Stack at the last used position of the array?

A) Both peek and pop would require linear time.B) Both push and pop would require linear time.


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C) The Stack could not be used to check balanced parentheses.D) The Stack could not be used to evaluate postfix expressions.Section-2 electronics and electrical1. The ability of a material to remain magnetized after removal of the magnetizing force is known as

PermeabilityreluctancehysteresisretentivityAns:D

2. When a solenoid is activated, the force that moves the plunger is

an electromagnetic field

a permanent magnetic fieldvarying voltagea steady currentAns:A

3. Which of the following capacitors is polarized

micaceramicplastic-filmelectrolytic

Ans:D

4. In a series resonant band-pass filter, a lower value of Q results in

a higher resonant frequencya smaller bandwidtha higher impedancea larger bandwidth

Ans:D

5. A steady-state condition is reached when

the output voltage reaches the average value of the input voltagethe output voltage reaches the input voltagethe output voltage reaches approximately 63% of the input voltagethe output voltage reaches the effective value of the input voltageAns:A

6. An RC differentiator acts as a


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low-pass filterhigh-pass filterband-pass filterband-stop filterAns:B

7. A balanced three-phase, 50 Hz voltage is applied to a 3 phase, 4 pole, induction motor. When the motoris delivering rated output, the slip is found to be 0.05. The speed of the rotor m.m.f. relative to the rotorstructure is

1500 r.p.m.1425 r.p.m.25 r.p.m.75 r.p.m.Ans:D

Explanation: NS = 120f /P = 120 x 50 /4 =1500rpm

N = NS ( 1-s) = 1500 (1-0.05) = 1425

\relative speed = 1500 1425 = 75 rpm

8. A ceiling fan uses

split-phase motor.capacitor start and capacitor run motoruniversal motor.capacitor start motor.Ans:D

9. The drive motor used in a mixer-grinder is a

dc motor.induction motor.synchronous motor.universal motor.Ans:D

10. A 1:5 step-up transformer has 120V across the primary and 600 ohms resistance across the secondary.Assuming 100% efficiency, the primary current equals

0.2 Amp.5 Amps10 Amps.20 Amps.


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Ans:AExplanation: I1= V1 /R1 = 120/600 = 0.2 (h = 100%, losses are zero \V1 = VR = I1R1)

11. A 50 Hz, 3-phase induction motor has a full load speed of 1440 r.p.m. The number of

poles of the motor are

4.6.128.Ans:A

Explanation: N= Ns (1-S) = NSNS x S

1440 = Ns (1-S)

Ns = 1440 / (1-S)

Ns = (120 f/ p) = 120 x 50/p = 6000 p

Ns will be closer to N i.e 1440

When P=2 ; Ns = 3000 rpm , not close to N

When P=4 ; Ns = 1500 rpm , it is closer to N

Therefore P =4 for N=1440

12. In a 3-phase synchronous motor

the speed of stator MMF is always more than that of rotor MMF.the speed of stator MMF is always less than that of rotor MMF.the speed of stator MMF is synchronous speed while that of rotor MMF is zerorotor and stator MMF are stationary with respect to each other.Ans:D

Explanation: Because, Motor is magnetically locked into position with stator, the rotor poles are engagedwith stator poles and both run synchronously in same direction Therefore,

rotor & stator mmf are stationary w.r.t each other.

13. In a three phase transformer, if the primary side is connected in star and secondary


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side is connected in delta, what is the angle difference between phase voltage in the

two cases.

delta side lags by -30.

star side lags by -30.delta side leads by 30.star side leads by -30.Ans:C

Explanation: This is vector group and has +30 displacement. Therefore, delta side leads by +30.

14. Slip of the induction machine is 0.02 and the stator supply frequency is 50 Hz.

What will be the frequency of the rotor induced emf?

10 Hz.50 Hz.1 Hz.2500 Hz.Ans:CExplanation: Given : s = 0.02 ; f = 50 Hz

Therefore, frequency of rotor induced emf = s f

= 0.02 x 50 = 1.0 Hz

15. A 4 pole lap wound dc shunt motor rotates at the speed of 1500 rpm, has a flux of 0.4 mWb and thetotal number of conductors are 1000. What is the value of emf?

100 Volts.0.1 Volts.1 Volts.10 Volts.Ans:D

Explanation: Given N = 1500 rpm, F = 0.4 mWb, Z = 1000, P = 4, & A= 4

Therefore, Eb = NFPZ / 60 A

= 1500 x 0.4 x 4 x 1000 x 10-3 / 60 x 4

= 60/6 = 10 volts


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