EPI ELECTRICAL ENGINEERING EPI 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 Option figure Ans: B Q.11 In a 3 – phase induction motor running at slip ‘s’ the mechanical power developed in terms of air gap power 11 and 12 figure 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

Apr 16, 2013 EPI-Computer Science Sample Questions 1 The problems 3-SAT and 2-SAT are A) both in P B) both NP-complete C) NP-complete and in P respectively D) undecidable and NP-complete respectively Answer : (C) 2 Consider the following relation schema pertaining to a students database: Student (rollno, name, address) Enroll (rollno, courseno, coursename) where the primary keys are shown underlined. The number of tuples in the Student and Enroll tables are 120 and 8 respectively. What are the maximum and minimum number of tuples that can be present in (Student * Enroll), where ‘*’denotes natural join? A) 8, 8 B) 120, 8 C) 960, 8 D) 960, 120 Answer : (C) 3 Consider a relation scheme R = (A, B, C, D, E, H) on which the following functional dependencies hold : (A -> B, BC -> D, E -> C, D -> A). What are the candidate keys of R? A) AE, BE B) AE, BE, DE C) AEH, BEH, BCH D) AEH, BEH, DEH Answer : (D) 4 The goal of structured programming is to A) have well indented programs B) be able to infer the flow of control from the compiled code C) be able to infer the flow of control from the program text D) avoid the use of GOTO statements Answer : (C) 5 The tightest lower bound on the number of comparisons, in the worst ease, for comparison-based sorting is of the order of A) n B) n 2 C) n log n D) n log2 n Answer : (B) 6 A circuit outputs a digit in the form of 4 bits. 0 is represented by 0000,1 by 0001,..., 9 by 1001. A combinational circuit is to be designed which takes these 4 bits as input and outputs 1 if the digit ³ 5, and 0 otherwise. If only AND, OR and NOT gates may be used, what is the minimum number of gates required A) 2 B) 3 C) 4 D) 5 Answer : (C) 7 WA and B are the only two stations on an Ethernet. Each has a steady queue of frames to send. Both A and B attempt to transmit a frame, collide, and A wins the first backoff race. At the end of this successful transmission by A, both A and B attempt to transmit and collide. The probability that A wins the second backoff race is A) 0.5 B) 0.625 C) 0.75 D) 1.0 Answer : (A) 8 If 73x (in base-x number system) is equal to 54y (in base-y number system), the possible values of x and y are A) 8, 16 B) 10, 12 C) 9, 13 D) 8, 11 Answer : (D) 9 In a packet switching network, packets are routed from source to destination along a single path having two intermediate nodes. If the message size is 24 bytes and each packet contains a header of 3 bytes, then the optimum packet size is A) 4 B) 6 C) 7 D) 9 Answer : (D) 10 A Priority-Queue is implemented as a Max-Heap. Initially, it has 5 elements. The level-order traversal of the heap is given below: 10, 8,5,3,2 Two new elements 1 and 7 are inserted in the heap in that order. The level-order traversal of the heap after the insertion of the elements is A) 10,8,7,5,3,2,1 B) 10,8,7,2,3,1,5 C) 10,8,7,1,2,3,5 D) 10,8,7,3,2,1,5 Answer : (D) 11 Consider an operating system capable of loading and executing a single sequential user process at a time. The disk head scheduling algorithm used is First Come First Served (FCFS). If FCFS is replaced by Shortest Seek Time First (SSTF), claimed by the vendor to give 50% better benchmark results, what is the expected improvement in the I/O performance of user programs ? A) 50% B) 40% C) 25%br> D) 0% Answer : (D) 12 How many distinct binary search trees can be created out of 4 distinct keys? A) 5 B) 14 C) 24 D) 42 Answer : (B) Q-13 Select the one true statement. A) Every binary tree is either complete or full. B) Every complete binary tree is also a full binary tree. C) Every full binary tree is also a complete binary tree D) No binary tree is both complete and full. Q-14 Which data structure has the fastest insertion procedure? A) Binary search tree B) Ordered array C) Heap D) Unordered linked list E) Ordered linked list Q-15 What are the complexities of the insert, remove and search methods of a binary search tree in the worst case? A) insert is O(n), remove is O(n), search is O(n) B) insert is O(log n), remove is O(log n), search is O(n) C) insert is O(log n), remove is O(log n), search is O(log n) D) insert is O(log n), remove is O(log n), search is O(1) E) These methods can't be defined on a binary search tree Q-16 This Ethernet frame type is characterized by its use of the code AA in the SAP fields. A) Ethernet II B) Ethernet RAW C) Ethernet 802.2 D) Ethernet SNAP Q-17 Which of the following are examples of routed protocols? (Choose all that apply) A) IP B) IPX C) RIP D) OSPF E) AppleTalk Q-18 If switches are used to replace hubs on a network, which of the following statements is true? A) The number of broadcast domains will decrease B) The number of collision domains will increase C) The number of collision domains will decrease D) The number of broadcast domains will be zero Q-19 Full duplex Ethernet communication is only possible when: A. Systems are connected to same LAN segments B. Systems are connected to a bridged ports C. Systems are connected to their own switch port D. Systems are running over a fiber optic connection Q-20 SQL is the combination of A ) DDL and DQL B ) DDL , DML and DQL C ) DDL,DML,DQL and DCL D ) None of these Q-21 Which of the following applications may use a stack? A) A parentheses balancing program. B) Keeping track of local variables at run time. C) Syntax analyzer for a compiler. D) All of the above Q -22 Consider the implementation of the Stack using a partially-filled array. What goes wrong if we try to store the top of the Stack at location [0] and the bottom of the Stack at the last used position of the array? A) Both peek and pop would require linear time. B) Both push and pop would require linear time. C) The Stack could not be used to check balanced parentheses. D) The Stack could not be used to evaluate postfix expressions. Q-23 Select the one true statement. A) Every binary tree is either complete or full. B) Every complete binary tree is also a full binary tree. C) Every full binary tree is also a complete binary tree D) No binary tree is both complete and full. Q-24 Which data structure has the fastest insertion procedure? A) Binary search tree B) Ordered array C) Heap D) Unordered linked list E) Ordered linked list Q-25 What are the complexities of the insert, remove and search methods of a binary search tree in the worst case? A) insert is O(n), remove is O(n), search is O(n) B) insert is O(log n), remove is O(log n), search is O(n) C) insert is O(log n), remove is O(log n), search is O(log n) D) insert is O(log n), remove is O(log n), search is O(1) E) These methods can't be defined on a binary search tree Q-26 This Ethernet frame type is characterized by its use of the code AA in the SAP fields. A) Ethernet II B) Ethernet RAW C) Ethernet 802.2 D) Ethernet SNAP Q-27 Which of the following are examples of routed protocols? (Choose all that apply) A) IP B) IPX C) RIP D) OSPF E) AppleTalk Q-28 If switches are used to replace hubs on a network, which of the following statements is true? A) The number of broadcast domains will decrease B) The number of collision domains will increase C) The number of collision domains will decrease D) The number of broadcast domains will be zero Q-29 Full duplex Ethernet communication is only possible when: A. Systems are connected to same LAN segments B. Systems are connected to a bridged ports C. Systems are connected to their own switch port D. Systems are running over a fiber optic connection Q-30 SQL is the combination of A ) DDL and DQL B ) DDL , DML and DQL C ) DDL,DML,DQL and DCL D ) None of these Q-31 Which of the following applications may use a stack? A) A parentheses balancing program. B) Keeping track of local variables at run time. C) Syntax analyzer for a compiler. D) All of the above Q -32 Consider the implementation of the Stack using a partially-filled array. What goes wrong if we try to store the top of the Stack at location [0] and the bottom of the Stack at the last used position of the array? A) Both peek and pop would require linear time. B) Both push and pop would require linear time. C) The Stack could not be used to check balanced parentheses. D) The Stack could not be used to evaluate postfix expressions.