Here I am looking for the previous year Solved Question paper of UGC NET Computer Science Exam, can you please provide me the same???

As you are looking for the previous year Solved Question paper of UGC NET Computer Science Exam so here I am sharing the same with you
JUNE 2009

2. In order that a code is error correcting, the minimum Hamming distance should be :
(A) t
(B) 2t - 1
(C) 2t
(D) 2t + 1
Ans:-D
Explanation:- The error-detecting and error-correcting properties of a block ode depend on its hamming distance.
To reliably DETECT ’t’ errors, you need a distance t+1 code.
To CORRECT t errors, you need a distance 2t+1 code.

3. The boolean expression x’y’z + yz + xz is equal to :
(A) x
(B) y
(C) z
(D) x+y+z
Ans:-C
Explanation:- x’y’z + yz + xz
= z(x’y’ + y + x)
=z(x’ + y’ + y + x)
=z(x + x’ + y + y’)
=z(1 + 1)
=z.1
=z

4. The characteristic equation of a JK flip flop is:
(A) Qn+1 = J.Qn + K.Qn
(B) Qn+1 = J.Qn’ + K’.Qn
(C) Qn+1 = QnJ.K
(D) Qn+1=(J+K).Qn
Ans:- B
Explanation:Flip flops can be divided into four basic types. Each one of them has a different characteristic equation, circuit, table, graphical symbol etc. But all the flip flops have output signal Qn and Qn’.The different flip flops and their characteristic equations are as follows.
1. SR flip flop = Qnext= S + R’Q
2. JK flip flop = Equation given above.
3. D flip flop = Qnext = D
4. T flip flop = TQ’+T’Q
It is better to learn the different flip flops and their characteristic equation because they ask in the exam frequently.
The n+1 and n should appear as subscripts for Q.

5. In order to implement a n variable switching function, a MUX must have:
(A) 2 pow n inputs
(B) 2 pow n + 1 inputs
(C) 2 pow n-1 inputs
(D) 2 pow n - 1 inputs
Ans:- A
Explanation:- A multiplexer is a combinational circuit that receives binary information from one of 2 pow n input data lines and directs it to a single output line. In order to implement a n variable switching function, a MUX must have 2 pow n inputs. Explanation is available in Computer architecture book by Morris Mano. Pg 48.

6. The throughput of pure ALOHA is given by,
(A) S=G
(B) S=e pow 2G
(C) S=Ge pow 2G
(D) S=Ge pow -2G
Ans:-D
Another question which keeps repeating in the exam is throughput of slotted ALOHA. Learn that as well.

7. The Fiber Distributed Data Interface uses:
(A) single mode fibbers and LEDs
(B) multimode fibbers and LEDs
(C) single mode fibbers and ILDs
(D) multimode fibers and ILDs
Ans:- B
Explanation:-FDDI defines two types of optical fibbers. Single mode and multimode. Multimode finer uses LEDs as the light-generating device. Single mode fiber generally uses lasers.

8. To employ multi-access in GSM, users are given different:
(A) time slots
(B) bandpass filters
(C) handsets
(D) frequency bands
Ans:-D

9. With four programs in memory and with 80% average I/O wait, the CPU utilisation is?
(A) 60%
(B) 70%
(C) 90%
(D) 100%
Ans:-A
Explanation:-CPU utilisation is given by the formula
= 1 - P pow n
CPU utilisation is calculated from a probabilistic viewpoint. P stands for the fraction of time waiting for I/O to complete.
Number of processes in memory = n
The probability that all n processes are waiting for I/O is p pow n.
P=80%=80/100=0.8
n=4
CPU Utilization = 1 - p pow n
= 1 - (0.8) pow 4
= 1 - 0.4096
= 60%

10. Assume N segments in memory and a page size of P bytes. The wastage on account of internal fragmentation is:
(A) NP/2 bytes
(B) P/2 bytes
(C) N/2 bytes
(D) NP bytes
And:-Wasted memory due to internal fragmentation is NP/2 bytes

11. Assertion (A): Bit maps are not often used in memory management.
Reason (R): Searching a bit map for a run of given length is a slow operation.
(A) Both (A) and (R) are true and (R) is correct explanation for (A)
(B) Both (A) and (R) are true but (R) is not correct explanation for (A)
(C) (A) is true (R) is false
(D) (A) is false (R) is true
Ans:- A

12.The complete graph with four vertices has k edges where k is :
(A) 3
(B) 4
(C) 5
(D) 6
Ans:- D
Explanation:- A graph G is said to be complete if every vertex in G is connected to every other vertex in G. So a complete graph G must be connected. The number of edges is 6.
13. The octal equivalent of hexadecimal (A.B)16 is :
(A) 47.21
(B) 12.74
(C) 12.71
(D) 17.21
Ans:
Explanation:- (A.B) hex. A is 10 and B is 11 in hex.
(10.11)hex
=1010.1011
=Next step, group the bits in groups of 3 each.
=001 010. 101 100
=1 2. 54 is the right answer

14. A reduced state table has 18 rows. The minimum number of flip flops needed to implement the sequential circuit is:
(A) 18
(B) 9
(C) 5
(D) 4
Ans:-D
Explanation: If you have n rows, your circuit will have at least log base 2 n flip flops. Log base 2 18 is 4. So the correct answer is D.

15. What is the value of ‘b’ after the execution of the following code statements:
c=10;
b=++c+++c;
(A) 20
(B) 22
(C) 23
(D) None
Ans

16. Which of the following does not represent a valid storage class in ‘c’?
(A) Automatic
(B) static
(C) union
(D) extern
Ans:-C
Explanation:- The valid storage classes are extern, static, register and auto(automatic).

17. The friend functions are used in situations where:
(A) We want to have access to unrelated classes
(B) Dynamic binding is required
(C) Exchange of data between classes to take place
(D) None of the above.
Ans:- C


18. (i) DML includes a query language based on both relation algebra and tuple calculus
(ii) DML includes a query language based on tuple calculus
(iii) DML includes a query language based on relational algebra
(iv) DML includes a query language based on none of the relation algebra and tuple calculus. Which one is correct?
(A) (i) only
(B) (ii) only
(C) (iii) only
(D) (iv) only
Ans:- A

19. Suppose it takes a 100ns to access a page table and 20ns to access associative memory with a 90% hit rate, the average access time equals:
(A) 20 ns
(B) 28 ns
(C) 90 ns
(D) 100 ns
Ans:- B
Almost a similar question was asked in December 2008 question paper.Question no.9. Refer to the same. The hit rate is asked given the average access time.

20. There exists a construct which returns a value ‘true’ if the argument subquery is:
(A) empty
(B) non-empty
(C) in error
(D) none of the above
Ans:- B

21. Which construct in SQL is used to test whether a subquery has any tuples in its result?
(A) UNIQUE
(B) EXISTS
(C) GROUP BY
(D) EXCEPT
Ans: B

22. ORACLE supports:
(A) inner join and outer join only
(B) outer join and semi join only
(C) inner join, outer join, semi join only
(D) inner join, outer join, semi join and anti join
Ans:- D

23. Which two of the following are equivalent for an undirected graph G?
(i) G is a tree
(ii) There is at least one path between any two distinct vertices of G
(iii) G contains no cycles and has (n-1) edges
(iv) G has n edges
(A) (i) and (ii)
(B) (i) and (iii)
(C) (i) and (iv)
(D) (ii) and (iii)
Ans:-B

24. In a B tree of order m with p nodes the average number of splits is at most:
(A) 1/(m/2)-1
(B) (m/2)-1
(C) 1/(m/2)
(D) None
Ans:-B
25. The propositional formula given by the tree is:
Refer to the actual QP.
Ans:- D
Explanation:-None of the equations fit any of preorder,postorder or inorder listing.

26. Queuse is a _______list.
(A) LIFO
(B) LILO
(C) FILO
(D) FIFO
Ans:- D

27. In a full binary tree of height k, there are __________internal nodes.
(A) 2 pow k - 1
(B) 2 pow (k - 1)
(C) 2 pow k
(D) 2 pow k + 1
Ans:- A

28.A binary tree is said to have heap property if the elements along any path:
(A) from leaf to root are non-increasing
(B) from leaf to root are non-decreasing
(C) from root to leaf are non-decreasing
(D) from root to leaf are non-increasing
Ans:- D
Explanation:-Answer is in Schaum’s series book on Data structures with C++.
A binary tree is said to have the heap property if the elements along any path from root to leaf are non increasing. A heap is a complete binary tree that has the heap property. So the correct option is D.

29. X.25 protocol consists of:
(A) Physical and frame levels
(B) Frame and packet levels
(C) Physical, frame and packet levels
(D) None of the above.
Ans:-C

30. GSM/CDMA systems:
(A) are limited to very low speed data
(B) require no local loop wires
(C) are predominantly used for voice
(D) all of the above
Ans:-D

31. Usually information security in a network is achieved by:
(A) Layering
(B) Cryptography
(C) Grad of service
(D) None of the above
Ans:- B

32. The linker:
(A) is similar to interpreter
(B) uses source code as its input
(C) is required to create a load module
(D) none of the above
Ans:- D
Linker is a program that links several object modules and libraries to a single executable program.

33. In which addressing mode the operand is given explicitly in the instruction itself?
(A) Absolute mode
(B) Immediate mode
(C) Indirect mode
(D) Index mode
Ans:- B
Explanation:- In immediate addressing mode, the operand is given in the instruction itself.
Eg:- MOV AL,64H Move 64H to Al register
MOV Bx,0493H Move 0493H to Bx register.

34. A compiler that runs on one machine and produces code for a different machine is called:
(A) Cross compilation
(B) One pass compilation
(C) Two pass compilation
(D) None of the above
Ans:- A

35. Any syntactic construct that can be described by a regular expression can also be described by a:
(A) Context sensitive grammar
(B) Non context free grammar
(C) Context free grammar
(D) None of the above
Ans:- C

36. Find the odd man out:
(A) tail
(B) cut
(C) wart
(D) sed
Ans:- C
Explanation:- tail, cut and sed are unix commands. wart is not.

37. Which of the following changes permission to deny write permission to group and others?
(A) chmod go-w filex
(B) chmod go=w filex
(C) chmod go w files
(D) None of the above
Ans:- A
Explanation:- chmod is the command used for changing file permissions. go stands for group and others. The minus symbol removes the permission. ‘w’ stands for write. So, go-w stands for removing the write permission from group and others for the file filed.

38. Variable partition memory management technique with compaction results in:
(A) Reduction of fragmentation
(B) Minimal wastage
(C) Segment sharing
(D) None of the above
Ans:- A

39. Capability Maturity Model is meant for:
(A) Product
(B) Process
(C) Product and Process
(D) None of the above
Ans:- B

40. In the light of software engineering software consists of:
(A) Programs
(B) Data
(C) Documentation
(D) All of the above
Ans:- D

41. Which one of the following ISO standard is used for software process?
(A) ISO 9000
(B) ISO 9001
(C) ISO 9003
(D) ISO 9000-3
Ans:- D

42. Which of the following is used for test data generation?
(A) White box
(B) Black box
(C) Boundary-value analysis
(D) All of the above
Ans:-C
Explanation:- Boundary value analysis is a technique for test data selection.A test engineer chooses values that lie along data extremes.

43. Reverse engineering is the process which deals with:
(A) Size measurement
(B) Cost measurement
(C) Design recovery
(D) All of the above
Ans:- C

44. The spacing between character pairs is called:
(A) Kerning
(B) x-height
(C) intercap
(D) serif
Ans:- A

45. When compared with analog cellular systems, an advantage of digital TDMA cellular system is that:
(A) it is less complicated
(B) it requires less of computer memory
(C) it conserves spectrum bandwidth
(D) it costs less
Ans:- C

46. E-commerce includes:
(A)B2C
(B) B2B
(C) C2C
(D) All of the above

47. A clustering technique that permits a convenient graphical display is:
(A) partition based clustering
(B) probabilistic model based clustering
(C) hierarchial clustering
(D) agglomerative clustering
Ans:- C

48. After sending a message, the sender should not be able to, at a later date, deny having sent the message, is referred to as:
(A) Authenticity
(B) Non-repudiability
(C) Auditability
(D) Repudiability
Ans:- B

49. The device which connects dissimilar LANs of different topologies using different sets of communication protocols so that information can flow from one to another is called:
(A) Router
(B) Bridge
(C) Gateway
(D) Switch
Ans:- C

50. We can not delete the ______icon but we can make it invisible.
(A) Recycle
(B) My computer
(C) Internet explorer
(D) None of the above
Ans:- A