HPCL Model Test Paper

HPCL Model Test Paper ? Electrical & Electronics Engineering Complete the following statement: 1. Space charge region around a p ? n junction a. Contains one type of mobile carriers depending on the level of doping of the p or n regions b. Does not contain mobile barriers c. Contains electrons only as free carriers d. Contains both free electrons and holes 2. What will be the consequences, if you remove the bypass capacitor across the emitter ? leg resistor in a CE amplifier? a. Decrease in voltage gain b. Increase in current gain c. Increase in voltage gain d. Decrease in current gain 4. On what does the frequency of the ripple in the output voltage of a 3 ? phase semi - converter depends upon? a. Firing angle and supply frequency b. Firing angle and load resistance c. Only on load circuit parameters d. Firing angle and load inductance 5. Which oscillator comprises of the highly stable resonance characteristic? a. Colpitts b. Hartley c. Weinbridge d. Crystal 6. ISDN handles data pertaining to a. Computer data only b. All digital services c. Speech only d. Speech and video 7. Which converter can operate in both 3 and 6 pulse modes? a. 3 phase full converter b. 1 phase full converter c. 3 phase half wave converter d. 3 phase semi ? converter 8. When do you use analog data acquisition system? a. Narrow bandwidth and high accuracy are required b. Wide bandwidth and low accuracy are required/sufficient c. Wide bandwidth and high accuracy are required d. Narrow bandwidth and low accuracy are required/ sufficient 9. With which of the option can you carry out the measurement of frequency? a. Wien?s bridge b. Owen?s bridge c. Schering?s bridge d. Maxwell?s inductance ? capacitance bridge 10. What will be the minimum number of line currents when the total number of branches in a network is = b and the graph of the network has ?n? number of branches? a. b ? n b. n c. b d. b + n 11. The equation of continuity defines the relation between: a. flux density and charge density b. electric field and magnetic field c. current density and charge density d. electric field and charge density 12. The E and H vector fields in a travelling electromagnetic wave are: a. Parallel in space b. Perpendicular in space c. H is in the direction of wave travel d. E is in the direction of wave travel 13. What will be the dominant cut off wavelength if for a rectangular wave guide 2.5cm * 1.2cm? a. 2.4 cm b. 5 cm c. 3.7 cm d. 2.5 cm 14. The device used for providing rate feedback in position control systems is called: a. Synchro b. Servomotor c. Potentiometer d. Tachogenerator 15. What will you use to eliminate Harmonics? a. Short pitch winding b. Skewing of rotor c. Distribution winding d. All of the above 16. What is the temperature of electrode in Arc furnace? a. 1500 degree b. 4500 degree c. 1000 degree d. 1500 to 3500 degree 17. Which of the element retains its energy after its source is disconnected? a. Capacitor b. Resister c. Thermistor d. Inductor 18. What does a sine wave generates when given as an input to Schmitt trigger? a. Saw tooth wave b. Sine wave c. Square wave d. Triangle wave 19. What does Hays Bridge and Schering Bridge used to measure? a. Capacitance, Inductance b. Inductance, Inductance c. Resistance, Capacitance d. Inductance, Capacitance 20. What will be the power factor if the two watts meters measurement?s reading ratio is ?(1-sqrt3):(1+sqrt3)? a. 0 b. 1 c. 0.866 d. 0.707 21. Choose which transistor mode gives the inverted output? a. Common collector b. Common base c. Common emitter d. None of the above 22. What are the elements in the circuit when V=100sin (1000t+46 deg), I=2Sin (1000t+80 deg)? a. R=40 ohm, L=30mH b. R=40 ohm, L=33.3 micro farads c. R=30 ohm, C=33.3 micro farads d. R=30 ohm, L=30mH 23. What is the function of a closed loop transfer when G(s) = (1-s)/s(s+2)? a. Marginally stable b. Stable c. Unstable d. All of the above 24. How can you improve the stability of transient? a. Auto re-closers b. By putting series capacitor c. By using dynamic resister d. All of the above 25. What material is generally used while making power diode? a. Germanium b. Silicon c. Both d. None of the above 26. In which mode will you find the diode when both the junction of NPN diode is reverse biased? a. Cut-off b. Inverted c. Active d. Saturation 27. Convert the 101101 Binary number into Octal number. a. 51 b. 65 c. 45 d. 55 28. In which band does the free electron exist? a. 2 b. 3 c. 1 d. Conduction band 29. What is the efficiency of half wave rectifier? a. 50% b. 100% c. 45% d. 86% 30. What will be the value of Acm when CMRR of an OP AMP is given as 80db and Ad is 20000? a. 2 b. 8 c. 4 d. 1 HPCL Placement Paper HPCL Model Test Paper ? Electrical & Electronics Engineering Complete the following statement: 1. Space charge region around a p ? n junction a. Contains one type of mobile carriers depending on the level of doping of the p or n regions b. Does not contain mobile barriers c. Contains electrons only as free carriers d. Contains both free electrons and holes 2. What will be the consequences, if you remove the bypass capacitor across the emitter ? leg resistor in a CE amplifier? a. Decrease in voltage gain b. Increase in current gain c. Increase in voltage gain d. Decrease in current gain 4. On what does the frequency of the ripple in the output voltage of a 3 ? phase semi - converter depends upon? a. Firing angle and supply frequency b. Firing angle and load resistance c. Only on load circuit parameters d. Firing angle and load inductance 5. Which oscillator comprises of the highly stable resonance characteristic? a. Colpitts b. Hartley c. Weinbridge d. Crystal 6. ISDN handles data pertaining to a. Computer data only b. All digital services c. Speech only d. Speech and video 7. Which converter can operate in both 3 and 6 pulse modes? a. 3 phase full converter b. 1 phase full converter c. 3 phase half wave converter d. 3 phase semi ? converter 8. When do you use analog data acquisition system? a. Narrow bandwidth and high accuracy are required b. Wide bandwidth and low accuracy are required/sufficient c. Wide bandwidth and high accuracy are required d. Narrow bandwidth and low accuracy are required/ sufficient 9. With which of the option can you carry out the measurement of frequency? a. Wien?s bridge b. Owen?s bridge c. Schering?s bridge d. Maxwell?s inductance ? capacitance bridge 10. What will be the minimum number of line currents when the total number of branches in a network is = b and the graph of the network has ?n? number of branches? a. b ? n b. n c. b d. b + n 11. The equation of continuity defines the relation between: a. flux density and charge density b. electric field and magnetic field c. current density and charge density d. electric field and charge density 12. The E and H vector fields in a travelling electromagnetic wave are: a. Parallel in space b. Perpendicular in space c. H is in the direction of wave travel d. E is in the direction of wave travel 13. What will be the dominant cut off wavelength if for a rectangular wave guide 2.5cm * 1.2cm? a. 2.4 cm b. 5 cm c. 3.7 cm d. 2.5 cm 14. The device used for providing rate feedback in position control systems is called: a. Synchro b. Servomotor c. Potentiometer d. Tachogenerator 15. What will you use to eliminate Harmonics? a. Short pitch winding b. Skewing of rotor c. Distribution winding d. All of the above 16. What is the temperature of electrode in Arc furnace? a. 1500 degree b. 4500 degree c. 1000 degree d. 1500 to 3500 degree 17. Which of the element retains its energy after its source is disconnected? a. Capacitor b. Resister c. Thermistor d. Inductor 18. What does a sine wave generates when given as an input to Schmitt trigger? a. Saw tooth wave b. Sine wave c. Square wave d. Triangle wave 19. What does Hays Bridge and Schering Bridge used to measure? a. Capacitance, Inductance b. Inductance, Inductance c. Resistance, Capacitance d. Inductance, Capacitance 20. What will be the power factor if the two watts meters measurement?s reading ratio is ?(1-sqrt3):(1+sqrt3)? a. 0 b. 1 c. 0.866 d. 0.707 21. Choose which transistor mode gives the inverted output? a. Common collector b. Common base c. Common emitter d. None of the above 22. What are the elements in the circuit when V=100sin (1000t+46 deg), I=2Sin (1000t+80 deg)? a. R=40 ohm, L=30mH b. R=40 ohm, L=33.3 micro farads c. R=30 ohm, C=33.3 micro farads d. R=30 ohm, L=30mH 23. What is the function of a closed loop transfer when G(s) = (1-s)/s(s+2)? a. Marginally stable b. Stable c. Unstable d. All of the above 24. How can you improve the stability of transient? a. Auto re-closers b. By putting series capacitor c. By using dynamic resister d. All of the above 25. What material is generally used while making power diode? a. Germanium b. Silicon c. Both d. None of the above 26. In which mode will you find the diode when both the junction of NPN diode is reverse biased? a. Cut-off b. Inverted c. Active d. Saturation 27. Convert the 101101 Binary number into Octal number. a. 51 b. 65 c. 45 d. 55 28. In which band does the free electron exist? a. 2 b. 3 c. 1 d. Conduction band 29. What is the efficiency of half wave rectifier? a. 50% b. 100% c. 45% d. 86% 30. What will be the value of Acm when CMRR of an OP AMP is given as 80db and Ad is 20000? a. 2 b. 8 c. 4 d. 1 HPCL Placement Paper HPCL Model Test Paper ? Electrical & Electronics Engineering Complete the following statement: 1. Space charge region around a p ? n junction a. Contains one type of mobile carriers depending on the level of doping of the p or n regions b. Does not contain mobile barriers c. Contains electrons only as free carriers d. Contains both free electrons and holes 2. What will be the consequences, if you remove the bypass capacitor across the emitter ? leg resistor in a CE amplifier? a. Decrease in voltage gain b. Increase in current gain c. Increase in voltage gain d. Decrease in current gain 4. On what does the frequency of the ripple in the output voltage of a 3 ? phase semi - converter depends upon? a. Firing angle and supply frequency b. Firing angle and load resistance c. Only on load circuit parameters d. Firing angle and load inductance 5. Which oscillator comprises of the highly stable resonance characteristic? a. Colpitts b. Hartley c. Weinbridge d. Crystal 6. ISDN handles data pertaining to a. Computer data only b. All digital services c. Speech only d. Speech and video 7. Which converter can operate in both 3 and 6 pulse modes? a. 3 phase full converter b. 1 phase full converter c. 3 phase half wave converter d. 3 phase semi ? converter 8. When do you use analog data acquisition system? a. Narrow bandwidth and high accuracy are required b. Wide bandwidth and low accuracy are required/sufficient c. Wide bandwidth and high accuracy are required d. Narrow bandwidth and low accuracy are required/ sufficient 9. With which of the option can you carry out the measurement of frequency? a. Wien?s bridge b. Owen?s bridge c. Schering?s bridge d. Maxwell?s inductance ? capacitance bridge 10. What will be the minimum number of line currents when the total number of branches in a network is = b and the graph of the network has ?n? number of branches? a. b ? n b. n c. b d. b + n 11. The equation of continuity defines the relation between: a. flux density and charge density b. electric field and magnetic field c. current density and charge density d. electric field and charge density 12. The E and H vector fields in a travelling electromagnetic wave are: a. Parallel in space b. Perpendicular in space c. H is in the direction of wave travel d. E is in the direction of wave travel 13. What will be the dominant cut off wavelength if for a rectangular wave guide 2.5cm * 1.2cm? a. 2.4 cm b. 5 cm c. 3.7 cm d. 2.5 cm 14. The device used for providing rate feedback in position control systems is called: a. Synchro b. Servomotor c. Potentiometer d. Tachogenerator 15. What will you use to eliminate Harmonics? a. Short pitch winding b. Skewing of rotor c. Distribution winding d. All of the above 16. What is the temperature of electrode in Arc furnace? a. 1500 degree b. 4500 degree c. 1000 degree d. 1500 to 3500 degree 17. Which of the element retains its energy after its source is disconnected? a. Capacitor b. Resister c. Thermistor d. Inductor 18. What does a sine wave generates when given as an input to Schmitt trigger? a. Saw tooth wave b. Sine wave c. Square wave d. Triangle wave 19. What does Hays Bridge and Schering Bridge used to measure? a. Capacitance, Inductance b. Inductance, Inductance c. Resistance, Capacitance d. Inductance, Capacitance 20. What will be the power factor if the two watts meters measurement?s reading ratio is ?(1-sqrt3):(1+sqrt3)? a. 0 b. 1 c. 0.866 d. 0.707 21. Choose which transistor mode gives the inverted output? a. Common collector b. Common base c. Common emitter d. None of the above 22. What are the elements in the circuit when V=100sin (1000t+46 deg), I=2Sin (1000t+80 deg)? a. R=40 ohm, L=30mH b. R=40 ohm, L=33.3 micro farads c. R=30 ohm, C=33.3 micro farads d. R=30 ohm, L=30mH 23. What is the function of a closed loop transfer when G(s) = (1-s)/s(s+2)? a. Marginally stable b. Stable c. Unstable d. All of the above 24. How can you improve the stability of transient? a. Auto re-closers b. By putting series capacitor c. By using dynamic resister d. All of the above 25. What material is generally used while making power diode? a. Germanium b. Silicon c. Both d. None of the above 26. In which mode will you find the diode when both the junction of NPN diode is reverse biased? a. Cut-off b. Inverted c. Active d. Saturation 27. Convert the 101101 Binary number into Octal number. a. 51 b. 65 c. 45 d. 55 28. In which band does the free electron exist? a. 2 b. 3 c. 1 d. Conduction band 29. What is the efficiency of half wave rectifier? a. 50% b. 100% c. 45% d. 86% 30. What will be the value of Acm when CMRR of an OP AMP is given as 80db and Ad is 20000? a. 2 b. 8 c. 4 d. 1 HPCL Test Paper - Electrical & Electronics Engineering 1. Choose which of the below mentioned stands true for its justification. a. A transparent latch consists of a D ? flip flop b. A flip ? flop is used to store 1 ? bit of information c. Master slave flip flop is used to store 2 bits of information d. Race around condition occurs in JK flip flop when both the inputs are 1 2. Choose the correct option to identify the fastest read/writable memory? a. Flash b. PROM c. EEPROM d. None of the above 3. Which logic is used by odd parity generator? a. Analog b. Sequential c. Digital d. None of the above 4. If you have to implement AB+CD+EF, how many NAND gates will be required to do so? a. 2 b. 1 c. 3 d. 4 5. State the value of A?+1. a. 1 b. A c. A? d. None of the above 6. According to Boolean Algebra what is the value of 1+A+B+C a. A+B+C b. 1 c. A d. None of the above 7. How many number of 1?s are there in the binary expression ? 162*9+162*7+16*5+3? a. 23 b. 4 c. 6 d. 10 8. Choose the correct alternative that is used as a data selector. a. Decoder b. Modulator c. Encoder d. Demodulator 9. Which transistor will you use in enhancement mode? a. UJT b. MOSFET c. JFET d. NPN 10. Which of the following option consist of high cut ? off frequency? a. CE b. CB c. CC d. None of the above 11. What is the largest negative number be represented with 8 bits in 2?s compliment representation? a. -127 b. -256 c. -255 d. -128 12. State the range of generation voltage. a. Between 400 KV and 700 KV b. Between 11 KV and 33 KV c. Between 132 KV and 400 KV d. None of the above 13. Choose which of the following option falls true for hysteresis motor. a. Needs Dc excitation b. Is not a self ? starting motor c. Is a constant speed motor d. Cannot be run in reverse speed 14. Which heating method is independent of supply frequency? a. Dielectric heating b. Electric arc heating c. Induction heating d. Electric resistance heating 15. What is the power factor of a squirrel cage induction motor? a. Low at heavy load only b. Low at light load only c. Low at light and heavy load only d. Low at rated load only 16 .Choose the correct option which uses direct inward dialling as one of its feature. a. VPN b. PBX c. PSTN d. EPABX 17. Choose the correct option for identifying the two windings of a transformer? a. Not linked at all b. Conductively linked c. Electrically linked d. Inductively linked Fill in the blanks 18. In a stepper motor the angular displacement _______ a. It cannot be used for positioning of work tables and tools in NC machine b. Can be precisely controlled c. It cannot be readily interfaced with micro - computer based controller d. The angular displacement cannot be precisely controlled 19. The purpose of inducing emf in the primary of a transformer ______ a. Leads the flux by 90 degree b. Lags behind the flux by 90 degree c. Is in phase with the flux d. Is in phase opposition to that of flux 20. Which motor will you choose which can operate in both lagging as well as leading power factors? a. Synchronous motor b. Squirrel cage motor c. DC shunt motor d. Wound rotor induction motor 21. What will be the voltage regulation of a full load and 0.80 power factor lagging load transformer when a two winding single phase transformer has a voltage regulation of 4.5% at full load and unity power factor? a. 4.5% or more b. Less that 4.5% c. 4.5% d. More than 4.5 % 22. What is the armature mmf in a D.C machine? a. Rotating w.r.t field b. Stationary w.r.t armature c. Rotating w.r.t brushes d. Stationary w.r.t field 23. What will be the output of a step ? input is given to an op ? amp integrator? a. Rectangular wave b. A ramp c. A sinusoidal wave d. A triangular wave with DC bias 24. What will be the output voltage of a transformer if it is primarily energised from a square wave voltage source? a. A pulse wave b. A square wave c. A sine wave d. A triangular wave 25. How will a motor react if salient pole is running synchronously at no load and its field current is switched off? a. Come to a halt b. Continue to run at a speed slightly less than the synchronous speed c. Continue to run at synchronous speed d. Continue to run at a speed slightly more than the synchronous speed 26. Why should you always start the D.C series motor with load? a. It will fail to start b. It will not develop high starting torque c. At no load, it will rotate at dangerously high speed d. All the above mentioned are true 27. Which is the most suitable servomotor for low power application? a. A DC shunt motor b. A DC series motor c. An AC two ? phase induction motor d. An AC series motor 28. What will you use to take out the current from the stator of an alternator? a. Commutator segments b. Slip rings c. Carbon brushes d. Solid connections 29. When will be the voltage zero in a transformer? a. Leading p.f b. Zero p.f leading c. Unity p.f d. Lagging p.f 30. In audio amplification, which distortion will you least object? a. Frequency b. Harmonic c. Intermediation d. Phase 31. When the relative speed between the magnetic fields of stator and rotor does is zero under steady state operation? a. Synchronous machine b. DC machine c. Single phase induction machine d. 3 phase induction machine e. All of the above are true 32. What shall be the secondary output voltage if the primary winding of a 220/6V, 50 Hz transformer is energised by a 110V, 60 Hz supply? a. 3.0 V b. 3.6 V c. 2.5 V d. 6.0 V 33. Choose the correct option to identify whose protection is taken care by ?who relay?? a. Long lines only b. Short lines only c. Any line d. Medium lines only 34. What is the mechanical power developed in terms of air gap power Pg in a 3 phase induction motor running at slip ?s?? a. (s-1) Pg b. Pg/1-S c. 1-SPg-Answer d. S.Pg 35. The electromagnetic torque developed in proportional to what in a D.C series motor? a. 1a b. 12a-Answer c. 1/1a d. 1/12a 36. What is the frequency of the rotor current in a 3 phase 50 Hz, 4 pole induction motor at full load? a. 2 Hz b. 20 Hz c. Zero d. 50 Hz 37. What does the damper winding produce when a synchronous motor is running at a synchronous speed? a. Eddy current torque b. Damping torque c. No torque d. Torque aiding the developed torque 38. What is the unit of magnetic flux density? a. Bohr b. Weber/sec c. Gauss d. Tesla 39. Define bistable multi ? vibrator. a. Saw tooth wave generator b. Free running oscillator c. Crustal oscillator d. Triggered oscillator 40. Choose the correct mean by which the speed and torque of induction motor can be varied? a. Frequency control b. Stator voltage control c. Rotor voltage control d. All of the above HPCL Aptitude Questions HPCL Placement Paper 2011 1.How many litres of pure acid are there in 8 litres of 20% solution? A)1.4 B)1.5 C)1.6 D)2.4 Ans: C 2.The value of a machine depreciates at tbe rare of 10% every year. It was purchased 3 years ago . If it represent value is Rs. 8748, Its purchase price was: A) Rs.10,000 B)Rs. 11,372 C)Rs.12,000 D)Rs.12,500 Ans: C 3. X varies inversely as square of y. Given that y = 2 for x = 1. The value of x for y = 6 will be equal to A) 3 B) 9 C) 1/3 D) 1/9 Ans : D 4. If 10% of x = 20% of y, then x : y is equal to A) 1 : 2 B) 2 : 1 C) 5 : 1 D) 10 : 1 Ans : B 5.A theif is noticed by a policeman from a distance of 200 m. The thief starts running and the policeman chases him. The thief and the policeman run at the rate of 10km. and 11km. per hour respectively. what is the distance between them after 6 minutes? A)100m B) 150m C)190m C)200m 6. A starts business with Rs.3500 and after 5 months, B joins with A as his partner. After a year, the profit is divided in the ratio 2 : 3. What is B's contribution in the Capital ? A) Rs. 7500 B) Rs. 8000 C) Rs. 8500 D) Rs. 9000 Ans : D 7. Ronald and Elan are working on an assignment. Ronald takes 6 hours to type 32 pages on a computer, while Elan takes 5 hours to type 40 pages. How much time will they take, working together on two different computers to type an assignment of 110 pages ? A) 7 hours 30 minutes B) 8 hours C) 8 hours 15 minutes D) 8 hours 25 minutes Ans : C 8. A and B can do a piece of work in 72 days; B and C can do it in 120 days; A dn C can do it in 4 days. Who among these will take the least time if put to do it alone? A) 80 days B) 100 days C) 120 days D) 150 days Ans : C 9.From a group of 7 men and 6 women, five persons are to be selected to form a committee so that at least 3 men are there on the committee. In how many ways can it be done? A)564 B)645 C)735 D)756 Ans:D 10.In how many different ways can the letters of the word MACHINE be arranged so that the vowels may occupy only the odd position? A)210 B) 576 C)144 D)1728 Ans:B 11. Was Avinash early, on time or late for work? (I) He thought his watch was 10 minutes fast (II) Actually his watch was 5 minutes slow Ans. (D) 12. What is the value of A if A is an integer? (I) A4 = 1 (II) A3 + 1 = 0 13.Zinc and copper are melted together in the ratio 9:11 . What is the weight of melted mixture, if 28.8 Kg of zinc has been consumed in it? A) 58kg B) 60kg C) 64kg D)70kg 14. A person travels 12 km in the southward direction and then travels 5km to the right and then travels 15km toward the right and finally travels 5km towards the east, how far is he from his starting place? (A) 5.5 kms (B) 3 km (C) 13 km (D) 6.4 km Ans. (b) 15. X's father's wife's father's granddaughter uncle will be related to X as (A) Son (B) Nephew (C) Uncle (D) Grandfather Ans. (C) 16. Find the next number in the series 1, 3 ,7 ,13 ,21 ,31 (A) 43 (B) 33 (C) 41 (D) 45 Ans. (a) 17. If in a certain code "RANGE" is coded as 12345 and "RANDOM" is coded as 123678. Then the code for the word "MANGO" would be (A) 82357 (B) 89343 (C) 84629 (D) 82347 Ans. (D) 18. In a square, all the mid points are joined. The inner square is shaded. If the area of the square is A, what is the area of the shaded area? 19. If a car starts from A towards B with some velocity. Due to some problem in the engine after traveling 30km, the car goes with 4/5 th of its actual velocity The car reaches B 45 min later to the actual time. If the car engine fails after traveling 45km, the car reaches the destination B 36min late to the actual time What is the initial velocity of car and what is the distance between A and B in km 20. A person has Rs 100/- in his pocket, he can as 25 pencils or 15 books. He kept 15% of the money for traveling expenses and purchased 5 pencils. So how many books he can purchase with the remaining money. 21. Given following sequence, find the next term in the series: (i) 0, 2, 4, 6, 8, 12, 12, 20, 16, ____ Ans: 12 (ii) 3, 6, 13, 26, 33, 66, ___ Ans: 53 22. Three customers want haircut and a shave. In a saloon, two barbers operate at same speed. They take quarter of an hour for the haircut and 5 mins for the shave. How quickly can they finish the haircut and shave of these three customers? Ans: 30 minutes 23. A shopkeeper likes to arrange and rearrange his collection of stamps. He arranges them sometimes in pair, sometimes in bundle of three, sometimes in bundle of fours, occasionally in bundle of fives and sixes. Every time he's left with one stamp in hand after arrangement in bundles. But if he arranges in the bundle of seven, he's not left with any stamp. How many stamps does a shopkeeper have? Ans: 301 24. A large field of 700 hectares is divided into two parts. The difference of the areas of the two parts is one-fifth of the two areas. What is the area of the smaller part in hectares? A)225 B)280 C)300 D)315 Ans:D 25.3. Smita was making a cube with dimensions 5*5*5 using 1*1*1 cubes. What is the number of cubes needed to make a hollow cube looking of the same shape? A) 98 B)104 C)100 D) 61 HPCL Sample aptitude and reasoning to practice 1. Find out the pair of numbers that does not belong to the group for lack of common property - (a) 16-18 (b) 56-63 (c) 96-108 (d) 86-99 (Ans) Explanations : All the rest are in the ratio of 8 : 9. 2. In the following question, number of letters are skipped in between by a particular rule. Which of the following observes the rule ? (a) ACZXFG (b) CFXURI (c) CFIURX (d) CXFUIR (Ans) 3. Which one of the given responses would be a meaningful order of the following ? 1. Sentence 2. Word 3. Chapter 4. Phrase 5. Paragraph (a) 4, 3, 1, 2, 5 (b) 2, 3, 5, 4, 1 (c) 3, 5, 1, 4, 2 (Ans) (d) 1, 3, 2, 4, 5 4. Arrange the following words as per order in the dictionary - 1. Inhabit 2. Ingenious 3. Inherit 4. Influence 5. Infatuation (a) 1, 2, 3, 4, 5 (b) 5, 4, 1, 2, 3 (c) 4, 5, 2, 1, 3 (d) 5, 4, 2, 1, 3 (Ans) 5. Which one of letters when sequentially placed at the gaps in the given letter series shall complete it ? _ ab _ b _ aba _ _ abab (a) a bb aa (b) bb aa b (c) ab aa b (d) a aa ba (Ans) Explanations : a ab a b / a aba b / a abab Directions - In Q. 6 to 9, a series is given, with one/two term missing. Choose the correct alternative from the given ones that will complete the series. 6. 14, 19, 29, 49, 89, _?_ (a) 139 (b) 149 (c) 159 (d) 169 (Ans) 7. BMRG, DLTF, FKVE, HJXD, ? (a) JIZC (Ans) (b) JZIB (c) GIFB (d) MOLC 8. 121, 144, 289, 324, 529, 576, ? (a) 961 (b) 841 (Ans) (c) 900 (d) 729 9. 5, 21, 69, 213, 645, ? (a) 1670 (b) 1941 (Ans) (c) 720 (d) 1320 HPCL electrical engg questions HPCL ELECTRICAL ENGINEERING HPCL PART - I TYPICAL QUESTIONS & ANSWERS OBJECTIVE TYPE QUESTIONS 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 is about (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. (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 to (A)1a (B)12a-Answer (C)1/1a (D)1/12a Ans: B Q.11 In a 3 – phase induction motor running at slip ‘s’ the mechanical power developed in terms of air gap power Pg is (A)(s-1)Pg (B)Pg/1-S (C)1-SPg-Answer (D)S.Pg. In 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 angles of Q.16 The primary winding of a 220/6 V, 50 Hz transformer is energised from 110 V, 60 Hz supply. The 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 is zero 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.22 The most suitable servomotor for low power applications is (A) a dc series motor. (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 heating Ans: C Q.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 HPCL Electrical-Engineering-EE HPCL Placement Paper ? Electrical Engineering 1. State the range of generation voltage. a. Between 400 KV and 700 KV b. Between 11 KV and 33 KV c. Between 132 KV and 400 KV d. None of the above 2. Choose which of the following option falls true for hysteresis motor. a. Needs Dc excitation b. Is not a self ? starting motor c. Is a constant speed motor d. Cannot be run in reverse speed 3. Which heating method is independent of supply frequency? a. Dielectric heating b. Electric arc heating c. Induction heating d. Electric resistance heating 4. What is the maximum torque in a 3 phase induction motor? a. Does not depend on rotor resistance b. Is proportional to rotor resistance c. None of the above 5. What is the power factor of a squirrel cage induction motor? a. Low at heavy load only b. Low at light load only c. Low at light and heavy load only d. Low at rated load only 6. Choose the correct option for identifying the two windings of a transformer? a. Not linked at all b. Conductively linked c. Electrically linked d. Inductively linked 7. Fill in the blanks In a stepper motor the angular displacement ___ a. It cannot be used for positioning of work tables and tools in NC machine b. Can be precisely controlled c. It cannot be readily interfaced with micro - computer based controller d. The angular displacement cannot be precisely controlled 8. The purpose of inducing emf in the primary of a transformer _________ a. Leads the flux by 90 degree b. Lags behind the flux by 90 degree c. Is in phase with the flux d. Is in phase opposition to that of flux 9. Which motor will you choose which can operate in both lagging as well as leading power factors? a. Synchronous motor b. Squirrel cage motor c. DC shunt motor d. Wound rotor induction motor 10. What will be the voltage regulation of a full load and 0.80 power factor lagging load transformer when a two winding single phase transformer has a voltage regulation of 4.5% at full load and unity power factor? a. 4.5% or more b. Less that 4.5% c. 4.5% d. More than 4.5 % 11. What is the armature mmf in a D.C machine? a. Rotating w.r.t field b. Stationary w.r.t armature c. Rotating w.r.t brushes d. Stationary w.r.t field 12. What will be the output voltage of a transformer if it is primarily energised from a square wave voltage source? a. A pulse wave b. A square wave c. A sine wave d. A triangular wave 13. How will a motor react if salient pole is running synchronously at no load and its field current is switched off? a. Come to a halt b. Continue to run at a speed slightly less than the synchronous speed c. Continue to run at synchronous speed d. Continue to run at a speed slightly more than the synchronous speed 14. Why should you always start the D.C series motor with load? a. It will fail to start b. It will not develop high starting torque c. At no load, it will rotate at dangerously high speed d. All the above mentioned are true 15. Which is the most suitable servomotor for low power application? a. A DC shunt motor b. A DC series motor c. An AC two ? phase induction motor d. An AC series motor 16. What will you use to take out the current from the stator of an alternator? a. Commutator segments b. Slip rings c. Carbon brushes d. Solid connections 17. When will be the voltage zero in a transformer? a. Leading p.f b. Zero p.f leading c. Unity p.f d. Lagging p.f 18. When the relative speed between the magnetic fields of stator and rotor does is zero under steady state operation? a. Synchronous machine b. DC machine c. Single phase induction machine d. 3 phase induction machine e. All of the above are true 19. What shall be the secondary output voltage if the primary winding of a 220/6V, 50 Hz transformer is energised by a 110V, 60 Hz supply? a. 3.0 V b. 3.6 V c. 2.5 V d. 6.0 V 20. What is the mechanical power developed in terms of air gap power Pg in a 3 phase induction motor running at slip ?s?? a. (s-1) Pg b. Pg/1-S c. 1-SPg-Answer d. S.Pg 21. The electromagnetic torque developed in proportional to what in a D.C series motor? a. 1a b. 12a-Answer c. 1/1a d. 1/12a 22. What is the frequency of the rotor current in a 3 phase 50 Hz, 4 pole induction motor at full load? a. 2 Hz b. 20 Hz c. Zero d. 50 Hz 23. What does the damper winding produce when a synchronous motor is running at a synchronous speed? a. Eddy current torque b. Damping torque c. No torque d. Torque aiding the developed torque HPCL Electronics Question Paper HPCL electronics and electrical solved question papers, 1. Removing bypass capacitor across the emitter-leg resistor in a CE amplifier causes (A) increase in current gain. (B) decrease in current gain. (C) increase in voltage gain. (D)decrease in voltage gain. Ans: D 2. When a step-input is given to an op-amp integrator, the output will be (A) a ramp. (B) a sinusoidal wave. (C) a rectangular wave. (D) a triangular wave with dc bias. Ans: A 3. Hysteresis is desirable in Schmitt-trigger, because (A) energy is to be stored/discharged in parasitic capacitances. (B) effects of temperature would be compensated. (C) devices in the circuit should be allowed time for saturation and desaturation. (D) it would prevent noise from causing false triggering. Ans: C 4. Space charge region around a p-n junction (A) does not contain mobile carriers (B) contains both free electrons and holes (C) contains one type of mobile carriers depending on the level of doping of the p or n regions (D) contains electrons only as free carriers Ans: A 5. When an amplifier is provided with current series feedback, its (A) input impedance increases and output impedance decreases (B) input and output impedances both decrease (C) input impedance decreases and output impedance increases (D) input and output impedances both increase Ans: D 6. The fan-out of a MOS-logic gate is higher than that of TTL gates because of its (A) low input impedance (B) high output impedance (C) low output impedance (D) high input impedance Ans: D 7. A highly stable resonance characteristic is the property of a ____ oscillator. (A) Hartley (B) Colpitts (C) Crystal (D) Weinbridge Ans. (C) 8. A phase shift oscillator uses __________________. (A) LC tuning (B) Piezoelectric crystal (C) Balanced bridge (D) Variable frequency operation Ans. (C) 9. A bistable multivibrator is a (A) Free running oscillator. (B) Triggered oscillator. (C) Saw tooth wave generator. (D) Crystal oscillator Ans:B 10. The number of point to point links required in a fully connected network for 50 entities is (A) 1250 (B) 1225 (C) 2500 (D) 50 Ans: (C) 11. The ________is a circuit-switched network, while the ______is a packet-switched network. (A) Telephone, ATM (B) SONET and FDDI (C) Satellite, Telephone (D) FDDI and SONET Ans: (A) 12. Direct inward dialling is used as a feature in (A) PSTN. (B) PBX. (C) EPABX. (D) VPN. Ans: (C) 13. ISDN handles data pertaining to (A) All digital services (B) Speech and Video (C) Computer data only (D) Speech only Ans: (A) 14. A BJT operates as a switch (A)under small signal conditions (B)with no signal condition (C)in the active region of transfer characteristic (D)under large signal conditions Ans:D 15. Bulk power transmission over long HVDC lines are preferred, on account of (A)low cost of HVDC terminals (B)no harmonic problems (C)minimum line power losses (D)simple protection Ans:C 16. A converter which can operate in both 3-pulse and 6-pulse modes is (A)1-phase full converter (B)3-phase half wave converter (C)3-phase semiconverter (D)3-phase full converter Ans:C 17. A three-phase semiconverter feeds the armature of a separately excited dcmotor, supplying a nonzero torque. For steady-state operation, the motor armature current is found to drop to zero at certain instances of time. At suchinstances, a voltage assumes a value that is (A)equal to the instantaneous value of the ac phase voltage (B)equal to the instantaneous value of the motor back emf (C)arbitrary (D)zero Ans:B 18. The frequency of the ripple in the output voltage of a 3-phase semiconverter depends upon (A)firing angle and load resistance (B)firing angle and supply frequency (C)firing angle and load inductance (D)only on load circuit parameters Ans:B 19. In dielectric heating, the rate of heating cannot be increased by increasing the potential gradient because (A)Coupling problems become highly pronounced (B)Very high voltages are not easily available (C)Heating becomes non-uniform (D)Corona takes place Ans:D 20. The speed and torque of induction motors can be varied by which of thefollowing means? (A)Stator voltage control (B)Rotor voltage control (C)Frequency control (D)All of these Ans:D HPCL Civil Question Paper HPCL civil engineering questions with answers 1. When the load line coincides with the centroid of the rivet group, the rivets are subjected to (A) shear only (B) tension only (C) bending only (D) shear as well as tension Ans: (A) 2. An ISMB 500 is used as a beam in a multistory construction. From the viewpoint of structural design, it can be considered to be ‘laterally restrained’ when (A) the tension flange is laterally restrained (B) the compression flange is laterally restrained (C) the web is adequately stiffened (D) the conditions in both (A) and (C) are met. Ans: (B) 3. Deflection limitations over beams are imposed because excessive deflection may cause (A) undesirable twisting and distortion of end connections (B) problems in drainage system (C) psychological effect on users (D) All of the above Ans: (D) 4. Purlins are to be chosen for a roof truss of 20 m spam, 4 m rise. Trusses are spaced at 4.5 m centre-to-centre. A most efficient design results from the use of (A) angle sections (B) channel sections (C) circular hollow sections (D) square hollow sections Ans: (B) 5. How is water stored in an aquifer? (A). in an open underground lake (B). in cracks and spaces in rocks (C). in impermeable rock (D). in wells and springs Ans:B 6. How do droplets become heavy enough so that the droplets fall as rain or snow? (A). The droplets gain mass from condensation within the clouds. (B). When evaporation occurs, extra water vapors forms into more droplets. (C). The droplets bump together and form larger droplets. (D). The hotter air allows the droplets to solidify and fall from the clouds. Ans:C 7. What causes water to rise out of the ground in hot springs? (A). Earth’s core heats the water, making the hotter water less dense. (B). A pump is used to bring water to Earth’s surface. (C. Gravity pulls water down through permeable materials. (D). A nearby volcano heats the water, making the hotter water less dense Ans:D 8. Mercury is a hazardous chemical. Which item does not contain mercury? (A) Computer disks (B) Blinking lights in sneakers (C) Fluorescent light bulbs (D) Thermometers Ans:A 9. Which items are recyclable? (A) Plastic milk jugs (B) Cereal boxes (C) Aluminum soda cans (D) All of the above Ans:D 10. How long does it take Styrofoam to break down in a landfill? (A) 10 Years (B) 50 Years (C) 100 Years (D) 500 Years Ans:D 11. Used oil should be disposed of by.. (A) Dumping it on your driveway (B) Watering it down and spreading it as a fertilizer (C) Collecting it in a sealed container and taking it to an oil changing business (D) Keeping in the garage for 10 years before throwing it away in the trash Ans:C 12. Fatigue strength of a rod subjected to cyclic axial force is less than that of a rotating beam of the same dimensions subjected to steady lateral force because (A) Axial stiffness is less than bending stiffness (B) Of absence of centrifugal effects in the rod (C) The number of discontinuities vulnerable to fatigue are more in the rod (D) At a particular time the rod has only one type of stress whereas the beam has both the tensile and compressive stresses Ans:D 13. A solid uniform metal bar of diameter D and length L is hanging vertically from its upper end. The elongation of the bar due to self weight is: (A) Proportional to L and inversely proportional to D2 (B) Proportional to L2 and inversely proportional to D2 (C) Proportional of L but independent of D (D) Proportional of U but independent of D Ans:A 14. If the value of Poisson's ratio is zero, then it means that [IES-1994] (A) The material is rigid. (B) The material is perfectly plastic. (C) There is no longitudinal strain in the material (D) The longitudinal strain in the material is infinite Ans:A 15. Lueder' lines on steel specimen under simple tension test is a direct indication of yielding of material due to slip along the plane [IAS-1997] (A) Of maximum principal stress (B) Off maximum shear (C) Of loading (D) Perpendicular to the direction of loading Ans:B 16. What is the cause of failure of a short MS strut under an axial load? [IAS-2007] (A) Fracture stress (B) Shear stress (C) Buckling (D) Yielding Ans:D 17. Torsion reinforcement provided at the corners of a two-way slab (A) distributes bending moment uniformly (B) prevents corners from lifting (C) controls cracking at corners (D) does not allow any twist at corners. Ans: (C) 18. If a two-way slab is found to be unsafe in shear, then the preferred remedy is (A) to provide shear stirrups (B) to increase the flexural reinforcement by 15% (C) to increase the thickness of the slab adequately (D) to increase the distribution reinforcement in edge strips Ans: (C) 19. According to the Indian Standard Specifications, concrete should be cured under a humidity of (A) 90% (B) 80% (C) 70% (D) 60% ANS: (A) 20. The radial splits which are wider on the outside of the log and narrower towards the pith are known as (A) star shakes (B) annular rings (C) cup shakes (D) heart shakes Ans: (A) HPCL Mechanical Question Paper HPCL Mechanical engineering questions with answers 1. Two identical containers hold two different ideal gases, X andY at the same temperature. The number of moles of each gas is the same. The molecular mass of gas X is twice that of gas Y .The ratio of the pressure of X to that of Y is (A) 12 (B) 1 (C)v 2 (D) 2 (E) 4 Ans:B 2. The temperature of an ideal gas is directly proportional to which of the following? (A) Average translational kinetic energy of the molecules (B) Average velocity of the molecules (C) Average potential energy of the molecules (D) Average momentum of the molecules (E) None of the above Ans:A 5. Materials which can store electrical energy are called (A) magnetic materials. (B) semi conductors. (C) dielectric materials. (D) super conductors. Ans: C 6. ACSR (Aluminium Conductor Steel Reinforced) are used as (A) over head transmission lines. (B) super conductors. (C) fuse (D) underground cables. Ans: A 7. A brittle material has: (A) Large plastic zone (B) No plastic zone (C) No elastic zone (D) Very little elastic zone. Answer: (B) 8. The maximum shear strain occurs on: (A) 90° with principal planes (B) 45° with principal planes (C) Principal planes (D) Independent of the principal planes. Answer: (B) 9. With rise in gas temperature, dynamic viscosity of most of the gases, (A) Increases (B) Decreases (C) Does not change significantly. (D) None of the above Answer: (A) 10. 11. 12. If the liquid fuel is highly viscous, the action required for proper burning in boiler is: (A).Pre-heating (B). Cooling (C). Mixing (D). Freezing Ans:A 13. Moisture, ash content, volatile matter and fixed carbon are measured for coal as part of: (A). Proximate analysis (B). Ultimate analysis (C). Proximate and utlimate analysis (D). None of the above Ans:A 14. What are the dimensions of kinematic viscosity of a fluid? (A) LT-2 (B) L2T-1 (C) ML-1T-1 (D)ML-2T-2 Ans:B 15. For a Newtonian fluid (A) Shear stress is proportional to shear strain (B) Rate of shear stress is proportional to shear strain (C) Shear stress is proportional to rate of shear strain (D) Rate of shear stress is proportional to rate of shear strain Ans:C 16. Forecasts used for new product planning, capital expenditures, facility location or expansion, and R&D typically utilize a (A). short-range time horizon (B). medium-range time horizon (C). long-range time horizon (D). naive method, because there is no data history (E). all of the above Ans:C 17. If two variables were perfectly correlated, the correlation coefficient r would equal (A). 0 (B). less than 1 (C). exactly 1 (D). -1 or +1 (E). greater than 1 Ans:D 18. The specific speed of a hydro turbine depends on (A).Actual speed (B).Head of operation (C).Output power (D).Actual speed ,head of operation & output power Ans:D 19. Governor is used with the steam turbine to regulate (A).Steam temperature (B).Steam pressure (C).Power output (D).Speed Ans:D 20. Increasing the number of periods in a moving average will accomplish greater smoothing, but at the expense of (A). manager understanding (B). accuracy (C). stability (D). responsiveness to changes Ans:D HPCL Electrical Question Paper HPCL electronics and electrical questions with answers 1. The unit of magnetic flux density is (A) gauss (B) tesla (C) bohr (D) weber/sec Ans: (B) 2. The equation of continuity defines the relation between (A) electric field and magnetic field (B) electric field and charge density (C) flux density and charge density (D) current density and charge density Ans: (D) 3. The current in a coil changes from 5A to 1A in 0.4 second. The induced voltage is 40 V. The self inductance in henry is (A) 1 (B) 2 (C) 4 (D) 10 Ans: (C) 4. The maximum power will be transferred from a voltage source to a load when (A) the source impedance is half that of the load impedance (B) the source impedance is equal to that of the load impedance (C) the source impedance is twice that of the load impedance (D) both source and load impedances must be zero Ans: (B) 5. The total number of branches in a network is equal to b. The graph of the network has n number of branches. The minimum number of line currents is (A) b+n (B) b (C) b-n (D) n Ans: (C) 6. In a travelling electromagnetic wave, E and H vector fields are (A) perpendicular in space . (B) parallel in space. (C) E is in the direction of wave travel. (D) H is in the direction of wave travel. Ans: C 7. A wave is incident normally on a good conductor. If the frequency of a plane electromagnetic wave increases four times, the skin depth, will (A) increase by a factor of 2. (B) decrease by a factor of 4. (C) remain the same. (D) decrease by a factor of 2. Ans: D 8. A hollow rectangular waveguide acts as a (A) High pass filter (B) Low pass filter (C) Band pass filter (D) Low frequency radiator Ans: A 9. Divergence theorem is applicable for (A) static field only (B) time varying fields only (C) both static and time varying fields (D) electric fields only Ans: C 10. For a rectangular wave guide, 2.5cm x 1.2cm, dominant cut off wavelength is (A) 5 cm (B) 2.5 cm (C) 2.4 cm (D) 3.7 cm Ans: A 11. When a steady current is passed through a ballistic galvanometer, then the deflection will be (A) maximum (B) zero (C) twice the normal value as it depends on Hibbert magnetic standard (D) None of the above Ans: (B) 12. The measurement of frequency can be carried out with (A) Owen’s bridge (B) Wien’s bridge (C) Maxwell’s inductance-capacitance bridge (D) Schering’s bridge Ans: (B) 13. The following material is not used for making a piezoelectric transducer (A) Rochelle salt (B) Barium titanate (C) Chlorium sulphide (D) Quartz Ans: (C) 14The velocity factor of a transmission line (A) is governed by the relative permittivity of the dielectric. (B) is governed by the skin effect. (C) is governed by the temperature. (D) All of the above. Ans: A 15. By using feedback in control systems, the sensitivity to parameter variation is improved.This is achieved at the cost of (A) stability (B) loss of system gain (C) transient response (D) reliability Ans: (B) 16. 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: (B) 17. In position control systems, the device used for providing rate feedback is called (A) potentiometer (B) synchro (C) tachogenerator (D) servomotor Ans: (C) 18. Given a badly underdamped control system, the type of cascade compensator to be used to improve its damping is (A) phase-lead (B) phase-lag (C) phase-lag-lead (D) notch filter Ans: (B) 19. Analog data acquisition systems are used when (A) wide bandwidth and low accuracy are required/sufficient (B) narrow bandwidth and low accuracy are required/sufficient (C) wide bandwidth and high accuracy are required (D) narrow bandwidth and high accuracy are required Ans: (A) 20. In a transmission line terminated by characteristic impedance, Zo (A) There is no reflection of the incident wave. (B) The reflection is maximum due to termination. (C) There are a large number of maximum and minimum on the line. (D) The incident current is zero for any applied signal. Ans: A HPCL Technical Questions HPCL Previous year Question paper for Chemical Engineerin 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 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 Explanation: To connect two switches together, you would use a RJ45 UTP crossover cable. HPCL control Systems Question Papers 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 electronics electrical questions papers Hindustan Petroleum Corporation Limited ,HPCL issued notification for Officer Trainee vacancies.HPCL Syllabus for Officer Trainee consist of General aptitude and Professional Technical Aptitude|HPCL Previous Years question Papers Latest Company Profile of HPCL HPCL Officer Trainees recruitment Written Test Pattern and HPCL Latest 2011-2012 Selection Procedure HPCL stands for Hindustan Petroleum Corporation Limited (HPCL) careers tests Preparation |HPCL Latest 2011-2012 Sample Placement Papers HPCL written Test Practice Questions| HPCL quantitative aptitude Logical Reasoning Technical Questions Professional Knowledge Questions with answers HPCL Hindustan Petroleum Corporation Ltd Written test questions HPCL Written Test Procedures| Selection Methodology 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 HPCL Technical-Other HPCL Exam Paper - Control system (Technical) 1. In an automatic control system, from the below mentioned options, which of the following elements is not used? a. Error detector b. Final control element c. Sensor d. Oscillator 2. What is a controller? a. A summer b. A amplifier c. A clipper d. A comparator 3. What will you use from the below mentioned options to increase the bandwidth? a. Phase lead network b. Phase lag network c. Both a & b in parallel d. Both a & b in cascade e. None of the above 4. For Mp, which amongst the following will be considered a good factor? a. Zero b. More than 2.2 c. Less than 1 d. Infinity e. Lying between 1.1 and 1.5 5. What is included in a type ? 0 systems? a. No pole at the origin b. Two poles at the origin c. Net pole at the origin d. Simple at one origin 6. State the disadvantage of a feedback system? a. Unreliability b. Insensitivity c. Instability d. Inaccuracy e. Inefficiency 7. What does an open loop control system include off? a. Internal system changes automatically taken care of b. Controlling action, depending upon human judgement c. Control action independent of the output or desired quantity d. Both a & b e. All of the above 8. What will you use to achieve high power amplification? a. Magnetic amplifier b. Push pull amplifier c. D.C. Generator d. DC amplifier e. Amplidyne 9. If you have to determine the stability of a control system using the time domain method, which of the following option will you choose? a. Nicholos chart b. Bode plot c. Root locus technique d. Nyquist plot e. Routh ? Hurwitz array f. Constant M and (fy) locus 10. Why do we not use inductance in lag network? a. Time delay and hysteresis losses b. High reactance c. Big size d. None of the above 11. How can you keep the noises low in a control system? a. Attenuating such frequencies at which external signals get coupled into the system b. Reducing the bandwidth c. Both a & b d. None of the above 12. In which of the following will you use transfer function of a system is defined as the ratio of output to input? a. Fourier transform b. Z ? transform c. Simple algebraic form d. Laplace transform 13. In between 200 Hz and 800 Hz how many octaves are present? a. 4 octave b. 1 octave c. 2 octave d. None of the above 14. The effect of which of the following is decreased by introduction of feedback? a. Error signals b. Disturbances c. Noise signals d. All of the above 15. What is the breakaway point of root loci? a. Open loop zeroes b. Closed loop zeroes c. Closed loop poles d. Open loop poles 16. Choose the correct option to describe the properties of a transfer function? a. It depends on system elements and not input and output of the system b. 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 c. It is ratio of two polynomials is S and assumes zero initial conditions d. It is a function which transfer one physical system into another physical system e. All of the above 17. Choose the correct option for nonlinear system. a. Speed control using SCR b. Automatic voltage regulator c. D.C servomotor with high field excitation d. Temperature control of a furnace using thermistor e. All of the above 18. What are the disadvantages of magnetic amplifier? a. Saturation of the core b. Time lag, less flexible, non ? sinusoidal waveform c. Low power consumption and isolation of the active circuit d. All of the above 19. What action will you take to reduce the steady state error? a. Decrease damping b. Decrease natural frequency c. Increase time constant d. Increase gain constant of the system e. Decrease damped frequency 20. What is a signal flow graph? a. Semi log graph b. Polar graph c. Log log graph d. A topological representation of a set of differentials equations e. A special type of graph for analysing modem control system 21. Two blocks G1(s) and G2 (s) can be cascaded to get resultant transfer function as: a. 1+G1(s) G2(s) b. G1(s) + G2(s) c. 1-G1(s)G2(s) d. G1(s)/G2(s) e. G1(s)G2(s) f. Two blocks cannot be cascaded 22. What should a servo system include compulsorily? a. Capacity to control position or its derivative b. Feedback system c. Power amplifier to amplify error d. All of the above e. None of the above 23. Where do you draw Nyquist plot? a. Centimetre graph paper b. Semi log graph paper c. Log log graph paper d. Polar graph paper 24. What happens to the stability when a root moves further away from imaginary axis? a. Decreases b. Increases c. Not affected d. None of the above 25. Choose the correct option that can be magnified by magnetic amplifier. a. Power b. Voltage c. Current d. None of the above