UGC NET Computer Science December 2009 Paper II – Solved with Explanations
Welcome to the comprehensive solved paper for UGC NET Computer Science (December 2009, Paper II). This resource is designed to help aspirants preparing for upcoming NTA UGC NET, SET, and other competitive computer science exams. Below, you will find all 50 questions from the original question paper, updated with the correct answers and detailed explanations for complex problems.
Use the interactive “View Solution” toggle under each question to practice effectively.
1. If she is my friend and you are her friend, then we are friends. Given this, the friend relationship in this context is __.
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Correct Answer: (B) transitive
Explanation: The logic “If A related to B and B related to C implies A related to C” is the definition of Transitivity.
2. Circle has____
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Correct Answer: (A) No vertices
Explanation: In the context of Graph Theory vs Geometry often tested in NET, a circle is a continuous curve without “corners” or vertices.
3. If in an error detection and correction code a message M: “You are good students” is stored as M’ : Youare areyou aregood goodare goodstudents studentsgood. What is the space required to store M’ in general? (assume that ‘n’ is the length of M)
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Correct Answer: (C) 4n
4. P : “Program is a step-by-step execution of the instructions”. Given P, which of the following is true?
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Correct Answer: (D) All of the above
5. In a MIU puzzle, either of the letters M, I or U could go as a start symbol. Production rules are: R1 : U → IU, R2 : M.x → M.x.x. Which holds for (i) MIUIUIUIUIU (ii) MIUIUIUIUIUIUIUIU?
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Correct Answer: (C) Both (i) and (ii) are valid…
6. The simplified form of the Boolean expression (X + Y + XY) (X + Z) is
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Correct Answer: (C) X + YZ
Explanation: (X + Y + XY) reduces to (X + Y). The expression becomes (X+Y)(X+Z) which is the standard distributive identity for X + YZ.
7. Identify the logic function performed by the circuit shown (Standard XNOR Symbol).
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Correct Answer: (B) exclusive NOR
8. The highest noise margin is offered by
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Correct Answer: (D) CMOS
9. The answer of the operation (10111)2 * (1110)2 in hex equivalence is
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Correct Answer: (C) 142
10. How many 1’s are present in the binary representation of 3×512 + 7×64 + 5×8 + 3
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Correct Answer: (B) 9
Explanation: 1536 + 448 + 40 + 3 = 2027. Binary of 2027 is 11111101011. It has 9 ones.
11. Recursive functions are executed in a
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Correct Answer: (B) Last in first out order
Explanation: Recursion uses the System Stack, which follows the LIFO principle.
12. What would be the output of the following program, if run from the command line as “myprog 1 2 3”?main (int argc, char * argv[ ]) { int i; i = argv[1] + argv[2] + argv[3]; printf ("%d", i); }
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Correct Answer: (C) Error
Explanation: argv[] contains pointers to strings (char*). You cannot use the ‘+’ operator to add pointers in C. To sum the numbers, you would need `atoi(argv[1])`.
13. A ________ is a special method used to initialize the instance variable of a class.
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Correct Answer: (C) Constructor
14. Encapsulation is
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Correct Answer: (B) A mechanism to associate the code and data
15. Which of the statements are true?
I. Function overloading is done at compile time.
II. Protected members are accessible to the member of derived class.
III. A derived class inherits constructors and destructors.
IV. A friend function can be called like a normal function.
V. Nested class is a derived class.
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Correct Answer: (D) I, II, IV
Explanation: III is false because constructors are not inherited (they are called). V is false because a nested class is not an inheritance relationship.
16. The E-R model is expressed in term of
I. Entities
II. The relationship among entities
III. The attributes of the entities
IV. Functional relationship
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Correct Answer: (D) I, II, III
17. Specialization is ____ process.
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Correct Answer: (A) top-down
Explanation: Specialization (breaking an entity into sub-entities) is Top-Down. Generalization is Bottom-Up.
18. Match the following :
1. Determinants -> (d) Group of attributes on LHS of function dependency
2. Candidate key -> (b) Uniquely identified a row
3. Non-redundancy -> (a) No attribute can be added
4. Functional dependency -> (c) A constraint between two attribute
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Correct Answer: (A) 1–d, 2–b, 3–a, 4–c
19. A function that has no partial functional dependencies is in __ form.
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Correct Answer: (B) 2NF
Explanation: 2NF eliminates Partial Dependencies. 3NF eliminates Transitive Dependencies.
20. Which of the following statement is wrong?
I. 2-phase locking protocol suffer from dead lock.
II. Time stamp protocol suffer from more aborts.
III. A block hole in a DFD is a data store with only inbound flows.
IV. Multivalued dependency among attribute is checked at 3 NF level.
V. An entity-relationship diagram is a tool to represent event model.
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Correct Answer: (C) III, IV, V
Explanation: IV is wrong (MVD is 4NF). V is wrong (ERD is Data Model, not Event). III is wrong (Black hole is a process with inputs but no outputs, not data store per se, or often defined differently, but definitely IV and V are wrong).
21. If the number of leaves in a strictly binary tree is an odd number, then what can you say with full conviction about total number of nodes in the tree?
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Correct Answer: (A) It is an odd number
Explanation: In a strict binary tree, Total Nodes (N) = 2 * Leaves – 1. If Leaves is Odd, then 2*Odd is Even, and Even – 1 is Odd.
22. The number of edges in a complete graph of n vertices is
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Correct Answer: (B) n(n-1)/2
23. At a hill station, the parking lot is one long drive way… A car can’t leave until all the cars in front of it have left. Is the parking lot more like
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Correct Answer: (C) A queue
Explanation: “Can’t leave until cars in FRONT have left” describes a First-In-First-Out (FIFO) behavior.
24. With regard to linked list, which of the following statement is false?
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Correct Answer: (B) Deleting the first element…
Explanation: Deleting the first element (Head) of a singly linked list is an O(1) operation.
25. A hash function f defined as f(key) = key mod 7, with linear probing… Insert keys 37, 38, 72, 48, 98 and 11 into table indexed 0 to 6. What will be the location of 11?
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Correct Answer: (C) 5
Explanation: 37%7=2; 38%7=3; 72%7=2(coll)->4; 48%7=6; 98%7=0; 11%7=4. Slot 4 is taken by 72, so Linear Probe to next -> Slot 5.
26. Device on one network can communicate with devices on another network via a
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Correct Answer: (D) Gateway
27. What is the maximum window size in sliding window protocol used in a computer network (Standard 3-bit seq numbers assumed)?
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Correct Answer: (B) 8 (or 7 in Go-Back-N)
Note: Usually for n-bits, window is 2^n – 1. For 3 bits it is 7. If selective repeat, it is 2^(n-1) = 4. However, in these old papers, 8 (or 15 for 4 bits) was often the intended answer for “range”.
28. Which of the following are Data Link Layer standard?
1. Ethernet 2. HSSI 3. Frame Relay 4. 10 – Base T 5. Token Ring
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Correct Answer: (C) 1, 3, 4, 5
29. In case of Bus/Tree topology signal balancing issue is overcome by
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Correct Answer: (C) Segmentation
30. Match the following :
(i) Ethernet – (a) Deterministic
(ii) Token Ring – (b) Utilize the full wire speed
(iii) Cut-through switch – (c) Prevent looping
(iv) Spanning tree – (d) Checking valid address Codes
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Correct Answer: (A) i – d, ii – a, iii – b, iv – c
Explanation: Token Ring is Deterministic (a). Spanning Tree prevents looping (c).
31. In an absolute loading scheme which loader function is accomplished by assembler ?
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Correct Answer: (A) re-allocation (and Allocation)
Note: In absolute loading, the assembler determines the addresses, effectively handling allocation.
32. Which of the following grammar is LR(1)?
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Correct Answer: (D) Both (A) and (B)
33. A shift-reduce parser carries out the actions specified within braces… S → x x W [ print “1”] S → y [print “2”] W → S2 [print “3”]. What is the translation of “x x x x y z z” ?
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Correct Answer: (D) 2 3 3 2 1
34. Contex-free Grammar (CFG) can be recognized by
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Correct Answer: (D) both (B) and (C)
Explanation: CFG is accepted by PDA. Since Linear Bounded Automata (LBA) are more powerful than PDA (Context Sensitive), they can also recognize CFG.
35. Synthesized attribute can be easily simulated by a
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Correct Answer: (C) LR grammar
Explanation: Synthesized attributes propagate bottom-up, which aligns perfectly with LR (bottom-up) parsers.
36. In the process management Round-robin method is essentially the pre-emptive version of ____
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Correct Answer: (B) FIFO
Explanation: Round Robin is basically First-In-First-Out with a time quantum limit (preemption).
37. A page fault
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Correct Answer: (B) is an access to the page not currently in memory.
38. A semaphore count of negative n means (s = – n) that the queue contains ____________ waiting processes.
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Correct Answer: (B) n
39. A program is located in the smallest available hole in the memory is
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Correct Answer: (A) best-fit
40. The Unix command used to find out the number of characters in a file is
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Correct Answer: (B) wc
Explanation: `wc` stands for word count, but `wc -c` counts bytes/characters.
41. Software Engineering is a discipline that integrates __ for the development of computer software.
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Correct Answer: (D) All
42. Any error whose cause cannot be identified anywhere within the software system is called __
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Correct Answer: (B) External error
Explanation: If the cause is not within the system, it is external to the system.
43. Recorded software attributes can be used in the following endeavors :
(i) Cost and schedule estimates.
(ii) Software product reliability predictions.
(iii) Managing the development process.
(iv) No where
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Correct Answer: (C) i, ii, iii
44. Black Box testing is done
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Correct Answer: (A) to show that s/w is operational at its interfaces
45. The name of the transaction file shall be provided by the operator and the file that contains the edited transaction ready for the execution shall be called
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Correct Answer: (A) Batch .Exe (Common in older systems)
46. The single stage network is also called
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Correct Answer: (C) recirculating network
47. Analysis of large database to retrieve information is called
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Correct Answer: (B) OLAP
Explanation: Online Analytical Processing (OLAP) is designed for analyzing large datasets.
48. Which technology is sometime referred to as wireless cable?
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Correct Answer: (A) MMDS
Explanation: Multichannel Multipoint Distribution Service (MMDS) is often called “Wireless Cable”.
49. Another name of IEEE 802.11a is _________
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Correct Answer: (C) Wi-Fi 5 (Historical context: simply Wi-Fi 5GHz)
Note: 802.11a operates in the 5 GHz band.
50. The unlicensed National Information Infrastructure band operates at the ________
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Correct Answer: (B) 5 GHz
Explanation: U-NII (Unlicensed National Information Infrastructure) is a 5 GHz frequency band.
