Download hpcl Placement Papers in MS Word and PDF Format for Job Interview

Today I appeared for my HPCL IT officers exam held on 12-Aug-2012 at Pune.

The exam was pretty similar to other PSU exams and very much according to the syllabus mentioned at its HPCL website.



Exam pattern was as follows :

Time : 2 HRS and 150 Questions for IT officers and other streams have 170 Questions to answer

Divisions of Questions:

60 Questions were general appti, English,Reasoning ,DI, Puzzles

Topics touched in these 60 Question :

ü Comprehension passage

ü Sentence Reaarangement

ü Synonyms

ü Use of Prepositions\Articles

ü Reasoning

ü Image Series Completion

ü Profit\Loss

ü Work and Time

ü Speed and distance

ü Data interpretation

ü Simple maths questions.



Tip to prepare : Pick any book of sample paper and make up your speed for these. No special and complex questions asked.



90 Questions were core-Technical, as Mine stream was of Computers so following are the topics from which we get the questions.



40 Questions from Programming like what would be the output of the code.



Tip : Prepare for the basic programming only.



Other 50 Questions from following topics :



Window and OS basics

Networking Basics

Firewall Basics

Unix\Linux commands

DB queries

Triggers

Cloud computing topics as per the syllabus like New developments in IT Cloud Computing/Cloud Storage

New developments in IT Cloud Computing/Deployment models

Computing/Deployment models

New developments in IT Cloud Computing/Hoblink

New developments in IT Cloud Computing/WTS



Questions were very straight forwards as per the syllabus mentioned on the site

HPCL Exam was held on 12/8/2012 at pitampura for chemical engineeering.

This time pattern was changed from last exam, equal % of technical and non technical questions but last time it was 100 non tech and 50 tech. questions.

No negative marking

Time= 2hrs

Toatal Non tech. question =85

Reading comprhn.= 05 on house violence

Preposition = 05

fillblank= 05

DI=05

sentence arrange=03

reasoining= 25

quant=30



Total Technical (Chemical Engineering) question=85

Polymer=30

CRE=10

Mass transfer=8

Heat transfer=8

mechanical operation= 4

Fluid mechanics=5

thermo=10

all the above mentioned figures are aproximate on memory based

for any type of query regarding PSU/GATE exam for chemical engineering.

HPCL model question paper for officer recruitment exam 2012

1. Dilute sulfuric acid is handled in vessels made of: (GATE-1989-9.i.a)
(a) Stainless steel
(b) Brass
(c) Lead
(d) Cast iron
Ans:c

2 ACSR (Aluminium Conductor Steel Reinforced) are used as
(A) over head transmission lines.
(B) super conductors.
(C) fuse
(D) underground cables.
Ans: A

2. At steady state, the temperature variation in a plane wall, made of two different solids
I and II is shown below:

figure

Then, the thermal conductivity of material I
(a) is smaller than that of II
(b) is greater than that of II
(c) is equal to that of II
(d) can be greater than or smaller than that of II
Ans:A

3.Brass is an alloy of
(A) copper and zinc.
(B) copper and iron.
(C) copper and Aluminum.
(D) copper and tin.
Ans: A

4. A gaseous reaction A ! 2B+C takes place isothermally in a constant pressure reactor. Starting with a gaseous mixture containing 50% A (rest inerts), the ratio of final to initial volume is found to be 1.6. The percentage conversion of A is (GATE-1992-2.c)
(a) 30
(b) 50
(c) 60
(d) 74
Ans:C

5.Property of material which allows it to be drawn out into wires is
(A) Ductility.
(B) Solder ability.
(C) Super conductivity.
(D) Malleability.
Ans: A

6.In n type semi conductor added impurity is
(A) pentavalent.
(B) divalent.
(C) tetravalent.
(D) trivalent.
Ans: A

7.Air enters an adiabatic compressor at 300 K. The exit temperature for a compression ratio of 3, assuming air to be an ideal gas ( = CP /CV = 7/5) and the process to be reversible, is
(A) 300(3 2/7)
(B) 300(3 3/5)
(C) 300(3 3/7)
(D) 300(3 5/7)
Answer: (a) For reversible adiabatic process PV = constant.

8.Phenol and Formaldehyde are polymerised to a resultant product known as
(A) PVC.
(B) bakelite.
(C) polyester.
(D) teflon.
Ans: B

9.The percentage of carbon in mild steel is
(A) 0.08 to 0.3 %
(B) 0.5 to 1.4 %
(D) 2.35 %
(D) 0.5 %
Ans: A

10. A rotameter, through which air at room temperature and atmospheric pressure is flowing, gives a certain reading for a flow rate of 100 cc/s. If helium (Molecular weight 4) is used and the rotameter shows the same reading, the flow rate is (GATE-1996-2.02)
(A) 26 cc/s
(B) 42 cc/s
(C) 269 cc/s
(D) 325 cc/s
Answer: (C)

11.Crystal size in a continuous crystalliser depends upon the
A. rate of heat transfer.
B. degree of turbulence.
C. degree of supersaturation.
D. all (a), (b) and (c).
Ans:D

12.When vaporisation takes place directly at the heating surface, it is called
A. film boiling
B. nucleate boiling
C. vapour binding
D. none of these
Ans:B

13.Fourier,s law applies to the heat transfer by
A. convection
B. radiation
C. conduction
D. all (a), (b) & (c)
Ans:C

14.Convective heat transfer co-efficient in case of fluid flowing in tubes is not affected by the tube length/diameter ratio, if the flow is in the __________ zone.
A.laminar
B.transition
C.both ,a, & ,b,
D. highly turbulent
Ans:D

15.In a solution containing 0.30 Kg mole of solute and 600 kg of solvent, the molality is
A. 0.50
B. 0.60
C. 2
D. 1
Ans:A

16.In batch distillation with constant reflux, overhead product composition __________ with time.
A.increases
B.decreases
C.does not vary
D.may increase on decrease, depends on the system
Ans:B

17.Which of the following plays an important role in problems of simultaneous heat and mass transfer ?
A. Lewis number
B. Schmidt number
C.Prandtl number
D.Sherwood number

18.Which of the following process sequences is correct for melt blown process?

A)preparation, extrusion, quenching, attenuation, lay-down, winding.
B)preparation, extrusion, drawing, attenuation, lay-down, winding.
C)preparation, extrusion, quenching, lay-down, attenuation, winding.
D)preparation, quenching, extrusion, attenuation, lay-down, winding

19.Which of the following bonding methods is generally following in spunbond process?

A)Needlepunching
B)Thermal calendar bonding
C)Chemical bonding
D)Hydroentanglement

20. Which of the following polymers is least likely to be optically transparent
A. Atactic polystyrene
B. Isotactic polystyrene
C. An ethylene/propylene random copolymer (50/50 composition)
D. A styrene/butadiene random copolymer

21.Styrene is almost a unique monomer, in that it can be polymerized by practically all methods
of chain polymerization.
A. Free radical
B. Anionic
C. Cationic
D. Co-ordination (i.e., with a catalyst)

22.What method would you use to synthesize a triblock copolymer?
A) Free radical polymerization
B) Anionic polymerization
C) Using a Ziegler Natta catalyst
D) By putting it into a bloody great pot and spitting on it to initiate polymerization
E) Condensation polymerization

23.In emulsion polymerization, the principal place where the monomer polymerizes is
A) Monomer droplets
B) Aqueous phase
C) Surfactant micelles
D) Surface of reactor
E) Air-liquid interface

24.Polypropylene produced commercially using a Ziegler-Natta catalyst is predominantly
A) Atactic
B) Isotactic
C) Syndiotactic

25.Which pairs of monomers would you use to make an ethylene/propylene random copolymer?

26.The Tromsdorff effect is
A. When the Swedish Bikini team drops from the sky with cases of Old Milwaukee beer.
B. When the rate of initiation increases as the nature of the polymerization mass (i.e. all the stuff in the pot) changes from the initial conditions
C. When the rate constant for propagation, kp, increases due to an increase in viscosity of the reaction mass
D. When the rate constant for termination decreases due to the same increase in viscosity.

27.The pressure of 20g of an ideal monatomic gas is tripled while the volume is halved. What happens tot he internal energy?

a)It stays the same
b) Increases
c) Decreases
d)Indeterminate

28.Area on a p-v diagram has units associated with

a) energy,
b) momentum
c) temperature
d) change in temp

29) The Pressure inside a commercial airliner is maintained at 1 atm(10^5 Pa). What is the net outward force exerted on a 1m x 2m cabin door if outside pressure is equal to .30 atm?

a)140,

b) 1,400,

c) 14,000

d) 140,000

30.A system acted on by surroundings receives 50J of heat while doing 20J of work. What is the net change of internal energy?

a) 70

b) 30

c) 0

d) -30

HPCL computer engineering questions with answers
1. Which layer 1 devices can be used to enlarge the area covered by a single LAN segment?

Switch
NIC
Hub
Repeater
RJ45 transceiver
A.1 only
B.1 and 3
C.3 and 4
D.5 only
Answer: Option D
Not that you really want to enlarge a single collision domain, but a hub (multiport repeater) will provide this for you.

2. Routers operate at layer _____. LAN switches operate at layer _____. Ethernet hubs operate at layer _____. Word processing operates at layer _____.
A.3, 3, 1, 7
B.3, 2, 1, none
C.3, 2, 1, 7
D.3, 3, 2, none

Answer: Option E
Explanation:
Routers operate at layer 3. LAN switches operate at layer 2. Ethernet hubs operate at layer 1. Word processing applications communicate to the Application layer interface,
but do not operate at layer 7, so the answer would be none.

3. Which of the following describe router functions?
A.Packet switching
B.Packet filtering
C.Internetwork communication
D.Path selection
E.All of the above
Answer: Option E
Explanation:
Routers provide packet switching, packet filtering, internetwork communication, and path selection.

4. Why does the data communication industry use the layered OSI reference model?It divides the network communication process into smaller and simpler components,
thus aiding component development, design, and troubleshooting.
It enables equipment from different vendors to use the same electronic components, thus saving research and development funds.
It supports the evolution of multiple competing standards and thus provides business opportunities for equipment manufacturers.
It encourages industry standardization by defining what functions occur at each layer of the model.
A.1 only
B.1 and 4
C.2 and 3
D.3 only

Answer: Option A
Explanation:
The main advantage of a layered model is that it can allow application developers to change aspects of a program in just one layer of the layer model,s specifications. Advantages of using the OSI layered model include, but are not limited to, the following:
It divides the network communication process into smaller and simpler components, thus aiding compo- nent development, design, and troubleshooting;
it allows multiple-vendor development through standardization of network components;
it encourages industry standardization by defining what functions occur at each layer of the model;
it allows various types of network hardware and software to communicate;
and it prevents changes in one layer from affecting other layers, so it does not hamper development.

5. A receiving host has failed to receive all of the segments that it should acknowledge. What can the host do to improve the reliability of this communication session?
A.Send a different source port number.
B.Restart the virtual circuit.
C.Decrease the sequence number.
D.Decrease the window size.

Answer: Option E
Explanation:
A receiving host can control the transmitter by using flow control (TCP uses Windowing by default). By decreasing the window size, the receiving host can slow down the transmitting host so the receiving host does not overflow its buffers.
7. What is the purpose of flow control?
A.To ensure that data is retransmitted if an acknowledgment is not received.
B.To reassemble segments in the correct order at the destination device.
C.To provide a means for the receiver to govern the amount of data sent by the sender.
D.To regulate the size of each segment.
Answer: Option A
Explanation:
Flow control allows the receiving device to control the transmitter so the receiving device,s buffer does not overflow.


8. Which three statements are true about the operation of a full-duplex Ethernet network?There are no collisions in full-duplex mode.A dedicated switch port is required for each full-duplex node.
Ethernet hub ports are preconfigured for full-duplex mode.In a full-duplex environment, the host network card must check for the availability of the network media before transmitting.
The host network card and the switch port must be capable of operating in full-duplex mode.
A.1, 2, and 5
B.2 and 4
C.2, 3 and 4
D.5 only

Answer: Option D
Explanation:
Full-duplex means you are using both wire pairs simultaneously to send and receive data. You must have a dedicated switch port for each node, which means you will not have collisions. Both the host network card and the switch port must be capable and set to work in full-duplex mode.

9. Which of the following are types of flow control?Buffering
Cut-through
Windowing
Congestion avoidance
A.1 and 2
B.1, 3 and 4
C.2 only
D.3 only
The common types of flow control are buffering, windowing, and congestion avoidance.

10. What are two purposes for segmentation with a bridge?To add more broadcast domains.
To create more collision domains.
To add more bandwidth for users.
To allow more broadcasts for users.
A.1 only
B.2 and 3
C.2 and 4
D.4 only

Answer: Option C
Explanation:
Bridges break up collision domains, which allow more bandwidth for users.

11. How does a host on an Ethernet LAN know when to transmit after a collision has occurred?In a CSMA/CD collision domain, multiple stations can successfully transmit data simultaneously.
In a CSMA/CD collision domain, stations must wait until the media is not in use before transmitting.You can improve the CSMA/CD network by adding more hubs.After a collision, the station that detected the collision has first priority to resend the lost data. After a collision, all stations run a random backoff algorithm. When the backoff delay period has expired, all stations have equal priority to transmit data.
A.1 and 3
B.2 and 4
C.1,3 and 4
D.2 and 5

Answer: Option C
Explanation:
Once transmitting stations on an Ethernet segment hear a collision, they send an extended jam signal to ensure that all stations recognize the collision. After the jamming is complete, each sender waits a predetermined amount of time, plus a random time. After both timers expire, they are free to transmit, but they must make sure the media is clear before transmitting and that they all have equal priority.


12. Which of the following types of connections can use full duplex?
Hub to hub
Switch to switch
Host to host
Switch to hub
Switch to host
A.1, 2 and 4
B.3 and 4
C.3 and 5
D.2, 3 and 5

Answer: Option A
Explanation:
Hubs cannot run full-duplex Ethernet. Full duplex must be used on a point-to-point connection between two devices capable of running full duplex. Switches and hosts can run full duplex between each other, but a hub can never run full duplex.

13. Acknowledgments, sequencing, and flow control are characteristics of which OSI layer?
A.Layer 2
B.Layer 3
C.Layer 4
D.Layer 7
Answer: Option D
Explanation:
A reliable Transport layer connection uses acknowledgments to make sure all data is transmitted and received reliably. A reliable connection is defined by a virtual circuit that uses acknowledgments, sequencing, and flow control, which are characteristics of the Transport layer (layer 4).

14. Which fields are contained within an IEEE Ethernet frame header?Source and destination MAC address Source and destination network address Source and destination MAC address and source and destination network address FCS field

A. 1 and 4
B.2 only
C.2 and 3 only
D. 3 only

Answer: Option C
Explanation:
An Ethernet frame has source and destination MAC addresses, an Ether-Type field to identify the Network layer protocol, the data, and the FCS field that holds the answer to the CRC.


15. What type of RJ45 UTP cable do you use to connect a PC,s COM port to a router or switch console port?
A.Straight-through
B.Crossover cable
C.Crossover with a CSU/DSU
D.Rolled
Answer: Option B

To connect to a router or switch console port, you would use an RJ45 UTP rolled cable.

16. How to implement a network medium that is not susceptible to EMI. Which type of cabling should you use?
A.Thicknet coax
B.Thinnet coax
C.Category 5 UTP cable
D.Fiber-optic cable
Answer: Option D
Explanation:
Fiber-optic cable provides a more secure, long-distance cable that is not susceptible to EMI interference at high speeds.

17. Segmentation of a data stream happens at which layer of the OSI model?
A.Physical
B.Data Link
C.Network
D.Transport
Answer: Option D
Explanation:
The Transport layer receives large data streams from the upper layers and breaks these up into smaller pieces called segments.

18. When data is encapsulated, which is the correct order?
A.Data, frame, packet, segment, bit
B.Segment, data, packet, frame, bit
C.Data, segment, packet, frame, bit
D.Data, segment, frame, packet, bit
Answer: Option E
Explanation:
The encapsulation method is data, segment, packet, frame, bit.

19. Which of the following are unique characteristics of half-duplex Ethernet when compared to full-duplex Ethernet?Half-duplex Ethernet operates in a shared collision domain.
Half-duplex Ethernet operates in a private collision domain.
Half-duplex Ethernet has higher effective throughput.
Half-duplex Ethernet has lower effective throughput.
A.2 only
B.1,2 and 3
C.1 and 4
D.4 only
Answer: Option B
Explanation:
Unlike full duplex, half-duplex Ethernet operates in a shared collision domain, and it has a lower effective throughput than full duplex.

20. What type of RJ45 UTP cable is used between switches?
A.Straight-through
B.Crossover cable
C.Crossover with a CSU/DSU
D.Crossover with a router in between the two switches
Answer: Option A

HPCL Hindustan Petroleum Corporation Ltd Written test questions HPCL Written Test Procedures| Selection Methodology

HPCL Hindustan Petroleum Corporation Ltd Technical Questions-Control systems questions
1. An open loop control system has its
(a) control action independent of the output or desired quantity
(b) controlling action, depending upon human judgment
(c) internal system changes automatically taken care of
(d) both (a) and (b)
(e) all (a),(b) and (c)


2. A servo system must have
(a) feedback system
(b) power amplifier to amplify error
(c) capacity to control position or its derivative
(d) all of these
(e) none of these


3. The major disadvantage of a feedback system may be
(a) Inaccuracy
(b) inefficiency
(c) Unreliability
(d) instability
(e) Insensitivity


4. Properties of a transfer function
(a) It is ratio of two polynomials is S and assumes zero initial conditions
(b) It depends on system elements and not input and output of the system
(c) Coefficients of the powers of S in denominator and numerator are all real constant. The order of denominator is usually greater than or equal to the order of numerator
(d) All of these
(e) It is a function which transfer one physical system into another physical system.


5. The classical analogous of a simple lever is
(a) Capacitor bridge
(b) transformer
(c) mutual inductor
(d) either of these


6. Two blocks G1(s) and G2(s) can be cascaded to get resultant transfer function as
(a) G1(s) + G2(s)
(b) G1(s) / G2(s)
(c) G1(s) G2(s)
(d) 1+G1(s) G2(s)
(e) 1-G1(s)G2(s)
(f) two blocks cannot be cascaded


7. The principles of homogeneity and super position can be applied to
(a) linear time invariant system
(b) non-linear time invariant system
(c) digital control system
(d) both (a) and (b)


8. Pick up the nonlinear system
(a) automatic voltage regulator
(b) d.c. servomotor with high field excitation
(c) temperature control of a furnaces using thermistor
(d) speed control using SCR
(e) all of these


9. Signal flow graph (SFG) is a
(a) polar graph
(b) semi log graph
(c) log log graph
(d) a special type of graph for analyzing modem control system
(e) a topological representation of a set of differential equations


10. Disadvantages of magnetic amplifier
(a) time lag, less flexible, non-sinusoidal waveform
(b) low power consumption and isolation of the active circuit
(c) saturation of the core
(d) all of these


11. Pick up false statement regarding magnetic amplifiers
(a) The gate coil of an ideal magnetic amplifier has either zero or infinite inductance
(b) Resistance of control and gate winding is very small
(c) Magnetic amplifier gas dropping load characteristics
(d) Magnetic amplifiers are not used to control the speed of d.c. shunt motor
(e) Magnetic amplifiers can be used in automatic control of electric drivers of higher rating.


12. High power amplification is achieved by using
(a) push pull amplifier
(b) amplidyne
(c) magnetic amplifier
(d) DC amplifier
(e) D.C. generator


13. Pick up false statement regarding servomotors
(a) The d.c. servomotors are lighter than equivalent a.c. servomotors
(b) The d.c. servomotors develops higher starting and reversing torque than equivalent a.c. servomotor.
(c) A drag cup a.c. servomotor has one windings on stator and other on rotor
(d) Output power of servomotors varies from 1/20 W to 100 W


14. To reduce steady state error
(a) decrease natural frequency
(b) decrease damping
(c) increase damped frequency
(d) increase time constant
(f) increase gain constant of the system


15. A good factor for Mp should be
(a) less than 1
(b) lying between 1.1 and 1.5
(c) more than 2.2
(d) zero
(e) infinity


16. Pick up false statement. Routh-Hurwitz criterion
(a) is used for determining stability of a system
(b) is an algebraic procedure
(c) gives the exact location of roots of the characteristic equation
(d) does not indicate relative degree of stability or instability


17. Which of the following is the time domain method of determining stability of a control system
(a) Bode plot
(b) Nyquist plot
(c) Nicholos chart
(d) Routh-Hurwitz array
(e) Constant M and (fy) locus
(f) Root locus technique


18. The technique which gives transient response quickly as well as stability information is
(a) Nyquist plot
(b) Routh-Hurwitz criteria
(c) Bode plot
(d) Root locus plot
(e) Nichols plot


19. The bandwidth can be increased by use of
(a) phase lag network
(b) phase lead network
(c) both (a) and (b) in cascade
(d) both (a) and (b) in parallel
(e) none of these


20. Nyquist plot is drawn on
(a) semi log graph paper
(b) log log graph paper
(c) polar graph paper
(d) centimeter graph paper


21. If the gain margin is positive and the phase margin is negative the system is
(a) stable
(b) unstable
(c) indeterminist


22. The Bode plot is applicable to
(a) all phase network
(b) minimum phase network
(c) maximum phase network
(d) lag lead network
(e) none of these


23. The valid relation between setting time ts and rise time tr is
(a) tr>ts
(b) ts>tr
(c) ts=tr
(d) none of these


24. As a root moves further away from imaginary axis the stability
(a) increases
(b) decreases
(c) not affected
(d) none of these


25. Flat frequency response means that the magnitude ratio of output to input over the bandwidth is
(a) variable
(b) zero
(c) constant
(d) none of above


26. How many octaves are between 200 Hz and 800 Hz
(a) Two octave
(b) One octave
(c) Four octave
(d) None of above


27. Human system can be considered as
(a) open loop system
(b) close loop system with single feedback
(c) close loop system with multivariable feedback
(d) none of these


28. In a feedback system the transient response
(a) Decays at constant rate
(b) gets magnified
(c) decays slowly
(d) decays more quickly


29. Transfer function of a system is used to calculate
(a) the steady state gain
(b) the main constant
(c) the order of system
(d) the output for any given input
(e) all of the above


30. Transfer function of a system is defined as the ratio of output to input in
(a) Laplace transform
(b) Z-transform
(c) Fourier transform
(d) Simple algebraic form


31. Introduction of feedback decreases the effect of
(a) disturbances
(b) noise signals
(c) error signals
(d) all the above


32. The system response of a system can be best tested with
(a) unit impulse input signal
(b) ramp input signal
(c) sinusoidal input signal
(d) exponentially decaying input signal


33. Which of the following is a closed loop system
(a) electric switch
(b) car starter
(c) de generator
(d) auto-pilot for an aircraft


34. Which of the following is used as an error detector
(a) potentiometer
(b) field controlled ac motor
(c) amplidyne
(d) armature controlled ac motor


35. The break away point of root loci are
(a) open loop poles
(b) closed loop poles
(c) open loop zeros
(d) closed loop zeros


36. Noise in a control system can be kept low by
(a) reducing the bandwidth
(b) attenuating such frequencies at which external signals get coupled into the system
(c) both (a) and (b)
(d) none of these


37. Main cause of absolute instability in the control system is
(a) parameters of controlling system
(b) parameters of controlled system
(c) parameters of feedback system
(d) error detector where the two signals are compared


38. Basically a controller is
(a) a amplifier
(b) a clipper
(c) a comparator
(d) a summer


39. A system with gain margin close to unity or a phase margin close to zero is
(a) highly stable
(b) highly oscillatory
(c) relatively stable
(d) none of these


40. Which of following elements is not used in an automatic control system
(a) sensor
(b) error detector
(c) oscillator
(d) final control element


41. AC systems are usually preferred to the DC systems in control applications because
(a) AC systems are cheaper
(b) AC systems are more stable
(c) AC systems have better performance characteristics and smaller in size
(d) all of these


42. A system has the transfer function (1-s)/(1+s); It is known as
(a) low pass system
(b) high pass system
(c) all pass system
(d) none of the above


43. In control systems, excessive bandwidth should be avoided because
(a) noise is proportional to bandwidth
(b) it leads to low relative stability
(c) it leads to slow speed of response
(d) none of these


44. In most systems, an increase in gain leads to
(a) larger damping ratio
(b) smaller damping ratio
(c) constant damping ratio
(d) none of these


45. A step function is applied to the input of a system and output is of the form y = t, the system is
(a) stable
(b) unstable
(c) not necessarily stable
(d) conditionally stable


46. Which of the following can be magnified by magnetic amplifier
(a) voltage
(b) current
(c) power
(d) none of above


47. The inductance is not used in lag network because of
(a) big size
(b) time delay and hysteresis losses
(c) high reactance
(d) none of these


48. Saturation in a stable control system can cause
(a) conditional stability
(b) over damping
(c) low level oscillations
(d) high level oscillations


49. Excessive noise in control systems can cause
(a) reduction in bandwidth
(b) reduction in gain
(c) saturation in amplifying stages
(d) oscillations


50. The type-0 system has
(a) net pole at the origin
(b) no pole at the origin
(c) simple at one origin
(d) two poles at the origin

HPCL Previous years electronics and Electrical questions with answers

1. Mho relay is usually employed for the protection of
a) Short lines only
b) Medium lines only
c) Long lines only
d) Any line
Ans: Long lines only

2. A modern power semiconductor device IGBT is combines the characteristics of
a) BJT and MOSFET
b) FCT and GTO
c) SCR and MOSFET
d) SCR and BJT
Ans: BJT and MOSFET

3. For a single-phase a.c. to d.c. controlled rectifier to operate in regenerative mode, which of the following conditions should be satisfied?
a) Half –controlled bridge, a 90°, source of e.m.f. in load
c) Full-controlled bridge, a > 90°, source of e.m.f. in load
d) Full-controlled bridge, a 90°, source of e.m.f. in load4. Which is the most suitable power device for high frequency ( more 100 kHz) switching application?
a) Power MOSFET
b) BJT
c) SCR
d) UJT
Ans: Power MOSFET

5. In a thyristor Latching current is ________ than Holding current
a) Equal
b) Less
c) Greater
d) None
Ans: Greater

6. The transfer function of a system is 10/(1+s) when operating as a unity feedback system, the steady state error to a step input will be
a) 0
b) 1/11
c) 10
d) Infinity
Ans: 1/11

7. Which one of the following statements for a dc machine which is provided with inter pole winding (IW) as well as compensating winding (CW) is correct
a) Both IW and CW are connected in series with Armature winding
b) Both IW and CW are connected in parallel with Armature winding
c) IW connected in series but CW is connected in parallel with Armature winding
d) CW connected in series but IW is connected in parallel with Armature winding
Ans: Both IW and CW are connected in series with Armature winding

8. A 0-10 mA PMMC ammeter reads 5mA in a circuit; its bottom control spring snaps out suddenly the meter will now read.
a) 5mA
b) 10mA
c) 2.5mA
d) 0
Ans: 0

9. A dc cumulatively compounded motor delivers rated load torque at rated speed. If series field is short circuited, then the armature current and speed will
a) Both increases
b) Both decreases
c) Increases and decreases
d) Decreases and increases
Ans: Both increases

10. Moving coil in dynamometer wattmeter connected
a) In series with fixed coil
b) Across supply
c) In series with load
d) Across load
Ans: Across supply

11. In an induction machine, if the air gap increased
a) Speed will be reduced
b) Efficiency will be improved
c) Power factor will be lowered
d) Breakdown torque will be reduced
Ans: Power factor will be lowered

12. A CRO screen has ten divisions on the horizontal scale. If a voltage signal 5 sin 314t+45 deg)is examined with a line base settings of 5 msec/div, the number of cycles of signal displayed on the screen will be
a) 0.5 cycles
b) 2.5 cycles
c) 5 cycles
d) 10 cycles
Ans: 2.5 cycles

13. A 3-phase 50HZ SCIM takes a power input of 30 KW at its full load speed of 1440 rpm. Total stator losses are 1 KW. The slip and rotor ohmic losses at full load are
a) 0.02, 600 W
b) 0.04, 580 W
c) 0.04, 1160 W
d) 0.04, 1200 W
Ans: 0.04, 1160 W

14. Thermocouple is used to measure
a) AC
b) DC
c) Both
d) None
Ans: Both

15. The two watt meters measurement the ratio of two meter readings is –(1-sqrt3):( 1+sqrt3) then the power factor is
a) 1
b) 0.866
c) 0.707
d) 0
Ans: 0.707

16. Hays bridge is used to measure___________ and Schering bridge is used to measure____________
a) Inductance, Inductance
b) Inductance, Capacitance
c) Capacitance, Inductance
d) Resistance, Capacitance
Ans: Inductance, Capacitance

17. When sine wave is given as input to Schmitt trigger then its generates
a) Sine wave
b) Saw tooth wave
c) Triangle wave
d) Square wave
Ans: Square wave

18. In Gauss Seidel method the following factors are influenced for operation
a) Acceleration factor
b) Selection of slack buss
c) Both
d) None
Ans: Selection of slack buss*

19.
i. (X’+Y’) A. Low-pass filter function
ii. (X’Y’) B. Sum
iii. (XY) C. NAND
D. Carry
E.NOR
a) i-C, ii-E, iii-D
b) i-C, ii-E, iii-B
c) i-C, ii-B, iii-D
d) i-C, ii-E, iii-A
Ans: i-C, ii-E, iii-D

20. The phase lead compensation is used to
a) Increase rise time and decrease overshoot
b) Decrease both rise time and overshoot
c) Increase both rise time and overshoot
d) Decrease rise time and increase overshoot
Ans: Decrease rise time and increase overshoot

21. Voltage feed back amplifier is a
a) Shunt-Shunt
b) Shunt-Series
c) Series-Shunt
d) Series- Series
Ans: Shunt-Shunt

22. In microprocessor the next instruction to be executed is stored in
a) Program Counter
b) Stack Pointer
c) Memory Pointer
d) Accumulator
Ans: Program Counter

23. The following element retains it energy after source is disconnected
a) Resister
b) Inductor
c) Capacitor
d) Thermistor
Ans:

24. In series RLC circuit at resonant
a) Voltage is in phase with current
b) Current is maximum
c) Inductive reactance = Capacitive reactance
d) All of the above
Ans: All of the above

25.For RC low pass filter R=100 K ohms, C= 5 micro farads then lower cutt of frequency is
a) 1 K HZ
b) 0 HZ
c) 381.3 HZ
d) Infinity
Ans:

26. V=100Sin (1000t+46 deg), I=2Sin (1000t+80 deg) what are the elements in the circuit
a) R=30 ohm, L=30 mH
b) R=30 ohm, C=33.3 micro farads
c) R=40 ohm, L=30 mH
d) R=40 ohm, L=33.3 micro farads
Ans: R=40 ohm, L=33.3 micro farads
27. L=10 mH, I=100Sin50t 0

28. In dielectric measurement, the dielectric loss is proportional to
a) F
b) V
c) I
d) Vsqr
Ans: Vsqr

29. G(s) = (1-s)/s(s+2) then closed loop transfer function is
a) Unstable
b) Stable
c) Marginally stable
d) All
Ans: Stable

30. G(s) = (1+0.5s)/(1+s) find which type of net work it is
a) Lead net work
b) Lag net work
c) Lag – Lead net work
d) Lead – Lag net work
Ans: Lag net work

31. Temperature of electrode in Arc furnace is
a) 1000 deg
b) 1500 deg
c) 1500 deg to 3500 deg
d) 4500 deg

32. In bode plot the point which separates the lower and upper frequencies is called
a) Critical point
b) Cut-off point

33. Nyquest stability is used to determine
a) Absolute Stability
b) Relative Stability
c) Both
d) None
Ans: Both*

34. When 220V dc shunt alternator generating the voltage at rated value. If direction of rotation is reversed, then alternator will
a) Build up its voltage with same polarity
b) Build up its voltage with opposite polarity
c) No build up of voltage
d) None
Ans: No build up of voltage

35. Over lap Angle depends on_________
a) Load inductance
b) Loa capacitance
c) Source inductance
d) Source capacitance
Ans: Source inductance

36. Area under speed time curve gives
a) Time
b) Speed
c) Distance
d) None
Ans: Distance

37. The regulation of Short Transmission lines depends up on
a) Distance of line
b) Frequency
c) Power factor
d) All
Ans: Power factor

38. Which of the following plant is having lowest load factor?
a) Diesel Plant
b) Pumped storage Plant
c) Thermal Plant
d) Nuclear Plant
Ans: Diesel Plan

39. For SR latch whent the out put is undesirable
a) 0, 0
b) 1, 0
c) 0, 1
d) 1, 1
Ans: 1, 1

40. For interrupting capacitive currents which Circuit Breaker (CB) is used
a) SF6 CB
b) Oil CB
c) Vacuum CB
d) Air blast CB
Ans: Vacuum CB

41. For V/F control, when frequency is increased in transformer
a) Core loss component current increases, Magnetizing component current decreases
b) Core loss component current increases, Magnetizing component current increases
c) Core loss component current decreases, Magnetizing component current decreases
d) Core loss component current decreases, Magnetizing component current increases
Ans: Core loss component current decreases, Magnetizing component current decreases
42. In ceiling fan the angle between auxiliary winding a main winding is
a) 0 deg
b) 90 deg
c) 180 deg
d) 360 deg
Ans: 90 deg

43. In a shaded pole motor, shaded rings are used to
a) Field flux production
Ans: Field flux production

44. Practical method of improving string efficiency
a) Increasing crass arms length
b) Using different size of insulators
c) Using different insulator materials
d) Using of guard rings
Ans: Increasing crass arms length*

45. In which type of fault all 3-phase components are equal
a) L-G
b) L-L
c) L-L-G
d) 3-Phase fault
Ans: 3-Phase fault

46. 11/220 KV 100 MVA transformers, the primary base voltage rating is 10 KV then secondary base KV is
a) 10 KV
b) 220 KV
c) 220/sqrt3
Ans: 220/sqrt3*

47. Water hamming effect is occurs in
a) Surge tank
b) Penstock
c) Turbine
d) Reservoir
Ans: Penstock

48. Transient stability can be improved by
a) By putting series capacitor
b) By using dynamic resister
c) Auto re-closers
d) All of the above
Ans: All of the above

49. If sending end voltage is Vs at no-load in a transmission line then receiving end voltage is if ABCD parameters of line is given
a) Vs
b) Vs/A
c) 0
d) Infinity
Ans: Vs/A

50. Harmonics are eliminated by using
a) Skewing of rotor
b) Distribution winding
c) Short pitch winding
d) All of the above
Ans: All of the above