## Monday, 29 June 2015

### UGC-CBSE NET JUNE 2015 COMPUTER SCIENCE AND APPLICATIONS PAPER-II ANSWER KEYS

CBSE NET JUNE 2015 COMPUTER SCIENCE AND APPLICATIONS PAPER-II SOLUTION

1:  How many strings of 5 digits have the property that the sum of their digits is 7?
1. 66
2. 330
3. 495
4. 99

2:  Consider an experiment of tossing two fair dice, one black and one red. What is the probability that the number on the black die divides the number on red die ?
1. 22 / 36
2. 12 / 36
3. 14 / 36
4. 6 / 36

3:  In how many ways can 15 indistinguishable fishes be placed into 5 different ponds, so that each pond contains atleast one fish?
1. 1001
2. 3876
3. 775
4. 200

4: Consider the following statements-
(a) Depth - first search is used to traverse a rooted tree.
(b) Pre - order, Post-order and Inorder are used to list the vertices of an ordered rooted tree.
(c) Huffman's algorithm is used to find an optimal binary tree with given weights.
(d) Topological sorting provides a labelling such that the parents have larger labels than their children.
Which of the above statements are true ?
1. (a) and (b)
2. (c) and (d)
3. (a) , (b) and (c)
4. (a), (b) , (c) and (d)

5:  Consider a Hamiltonian Graph (G) with no loops and parallel edges. Which of the following is true with respect to this Graph (G) ?
(a) deg (v) >= n / 2 for each vertex of G
(b)  | E(G) | >= 1 / 2 (n-1) (n-2) + 2 edges
(c) deg (v) + deg (w) >= n for every v and w not connected by an edge
1. (a) and (b)
2. (b) and (c)
3. (a) and (c)
4. (a), (b) and (c)

6:  Consider the following statements :
(a) Boolean expressions and logic networks correspond to labelled acyclic digraphs.
(b) Optimal boolean expressions may not correspond to simplest networks.
(c) Choosing essential blocks first in a Karnaugh map and then greedily choosing the largest remaining blocks to cover may not give an optirnal expression-
Which of these statement(s) is/ are correct
1. (a) only
2. (b) only
3. (a) and (b)
4. (a), (b) and (c)

7: Consider a full - adder with the following input values :
(a) x=1, y=0 and Ci(carry input) = 0
(b) x=0, y=1 and Ci = 1
Compute the values of S(sum) and C0 (carry output) for the above input values.
1. S=1 , C0= 0 and S=0 , C0= 1
2. S=0 , C0= 0 and S=1 , C0​= 1
3. S=1 , C0= 1 and S=0 , C0​= 0
4. S=0 , C0= 1 and S=1 , C0​= 0

8: "lf my computations are correct and I pay the electric bill, then I will run out of money. If I don't pay the electric biIl the power will be turned off. Therefore, if I don't run out of money and the power is still on then my computations are incorrect."
Convert this argument into logical notations using the variables c, b, r, p for propositions of computations, electric bills, out of money and the power respectively. (Where  ¬ means NOT)
1. if (c ∧ b) → r and ¬b → ¬p, then (¬r∧p)→¬c
2. if (c ∨ b) → r and ¬b → ¬p, then (r∧p)→c
3. if (c ∧ b) → r and ¬p → ¬b, then (¬r ∨ p)→¬c
4. if (c ∨ b) → r and ¬b → ¬p, then (¬r∧p)→ ¬c

9:  Match the following:
 List - I List - II (a) (p →q) ⇔ (¬q → ¬p) (i) Contrapositive (b) [(p ∧q) →r ]⇔ [p→ (q →r)] (ii) Exportation law (c) (p →q)⇔ [(p ∧ ¬q) →o] (iii) Reductio ad absurdum (d) (p⇔q)⇔ [(p →q) ∧(q→p)] (iv) Equivalence

(a)   (b)  (c)   (d)
1.      (i)   (ii)   (iii)  (iv)
2.      (ii)   (iii)   (i)  (iv)
3.      (iii)   (ii)   (iv)  (i)
4.      (iv)   (ii)   (iii)  (i)

10:  Consider a proposition given as :
" x ≥ 6, if  x2 ≥ 25 and its proof as:
If x ≥ 6, then x2 = x· x= 6· 6=36 ≥25
Which of the following is correct w.r.to the given proposition and its proof ?
(a) The proof shows the converse of what is to be proved.
(b) The proof starts by assuming what is to be shown.
(c) The proof is correct and there is nothing wrong.
1. (a) only
2. (c) only
3. (a) and (b)
4. (b) only

11: What is the output of the following program ?
(Assume that the appropriate preprocessor directives are included and there is no syntax error)
main ( )
{    char S[ ] = "ABCDEFGH";
printf ("%C",* (& S));
printf ("%s", S + 4);
printf ("%u", S);
/* Base address of S is 1000 */
}

1. ABCDEFGH1000
2. CDEFGH1000
3. DDEFGHH1000
4. DEFGH1000

12:  Which of the following, in C++, is inherited in a derived class from base class ?
1. constructor
2. destructor
3. data members
4. virtual methods

13: Given that x = 7.5, j = -1.0, n = 1.0, m = 2.0 the value of - - x + j = = x > n >= m is :
1. 0
2. 1
3. 2
4. 3

14:  Which of the following is incorrect in C++ ?
1. When we write overloaded function we must code the function for each usage.
2. When we write function template we code the function only once.
3. It is difficult to debug macros
4. Templates are more efficient than macros

15:  When the inheritance is private, the private methods in base class are in the ----------- derived class (in C++).
1. inaccessible
2. accessible
3. protected
4. public

16:  An Assertion is a predicate expressing a condition we wish database to always satisfy. The correct syntax for Assertion is :
1. CREATE ASSERTION',ASSERTION Name', CHECK',Predicate',
2. CREATE ASSERTION 'ASSERTION NAME'
3. CREATE ASSERTION, CHECK Predicate
4. SELECT ASSERTION

17:  Which of the following concurrency protocol ensures both conflict serializability and freedom from deadlock ?
(a) z-phase Locking
(b) Time stamp - ordering
1. Both (a) and (b)
2. (a) only
3. (b) only
4. Neither (a) nor (b)

18:  Drop Table cannot be used to drop a Table referenced by ------ constraint.
(a) Primary key (b) Sub key (c) Super key (d) Foreign key
1. (a)
2. (a), (b) and (c)
3. (d)
4. (a) and (d)

19:  Database applications were built directly on top of file system to overcome the following drawbacks of using filesystems
(a) Data redundancy and inconsistency
(b) Difficulty in accessing Data
(c) Data isolation
(d) Integrity problems
1. (a)
2. (a) and (d)
3. (a), (b) and (c)
4. (a), (b), (c) and (d)

20: For a weak entity set to be meaningful, lt must be associated with another entity set in combination with some of their attribute values, is called as :
1. Neighbour Set
2. Strong Entity Set
3. Owner entity set
4. Weak Set

21: Consider the given graph:

Its Minimurn Cost Spanning Tree is --------
1.
2. Second
3.
4.

22: The inorder and preorder Traversal of binary Tree are dbeafcg and abdecfg respectively.The post order traversal is ------
1. dbefacg
2. debfagc
3. dbefcga
4. debfgca

23: Level order Traversal of a rooted Tree can be done by starting from root and performing -
1. Breadth First Search
2. Depth first search
3. Root search
4. Deep search

24: The average case occurs in the Linear Search Algorithm when :
1. The item to be searched is in some where middle of the Array
2. The item to be searched is not in the array
3. The item to be searched is in the last of the array
4. The item to be searclred is either in the last or not in the array

25: To determine the efficiency of an algorithm the time factor is measured by
1. Counting micro seconds
2. Counting number of key operations
3. Counting number of statement
4. Counting kilobytes of algorithm

26: which of the following protocols is an application layer protocol that establishes, manages and terminates multimedis sessions?
1. Session Maintenance Protocol
2. Real - time Streaming Protocol
3. Real - time Transport Control Protocol
4. Session Initiation Protocol

27: Match the following port numbers with their uses :

 List-I List-II (a) 23 (i) World wide web (b) 25 (ii) Remote Login (c) 80 (iii) USENET news (d) 119 (iv) Email

(a)  (b)  (c)  (d)
1. (iv)   (i)  (ii)  (iii)
2. (ii)   (i)  (iv)  (iii)
3. (ii)   (iv)  (iii)   (i)
4. (ii)   (iv)  (i)   (iii)

28: Which of the following is not associated with the session layer ?
1. Dialog control
2. Token management
3. Semantics of the information transmitted
4. Synchronization

29: What is the size of the'total length' field in IPv 4 datagram ?
1. 4 bits
2. 8 bits
3. 16 bits
4. 32 bits

30: Which of the following isf are restriction(s) in classless addressing ?
1. The number of addresses needs to be a power of 2.
2. The mask needs to be included in the address to define the block.
3. The starting address must be divisible by lhe number of addresses in the block.
4. All of the above

31: Match the following:

 List-I List-II (a) Forward Reference Table (i) Assembler directive (b) Mnemonic Table (ii) Uses array data structure (c) Segment Register Table (iii) Contains machine OP code (d) EQU (iv) Uses linked list data structure

(a)   (b)   (c)  (d)
1. (ii)   (iii)  (iv)  (i)
2. (iii)   (iv)  (ii)  (i)
3. (iv)   (i)  (iii)  (ii)
4. (iv)   (iii)  (ii)  (i)

32: The translator which performs macro calls expansion is called :
1. Macro processor
2. Micro pre-processor
3. Macro pre-processor
4. Dynamic linker

33: If all the production rules have single non - terminal symbol on the left side, the grammar defined is:
1. context free grammar
2. context sensitive grammar
3. unrestricted grammar
4. phrase grammar

34: Which one from the following is false ?
1. LALR parser is Bottom - Up parser
2. A parsing algorithm which performs a left to right scanning and a right most deviation is RL (1).
3. LR parser is Bottom - Up parser.
4. In LL(1), the 1 indicates that there is a one - symbol look - ahead.

35: Which phase of compiler generates stream of atoms ?
1. Syntax analysis
2. Lexical Analysis
3. Code generation
4. Code optimization

36: A disk drive has 100 cylinders, numbered 0 to 99. Disk requests come to the disk driver for cylinders 12, 26, 24, 4, 42, 8 and 50 in that order. The driver is currently serving a request at cylinder 24- A seek takes 6 msec per cylinder moved. How much seek time is needed for shortest seek time first (SSTF) algorithm?
1. 0.984 sec
2. 0.396 sec
3. 0.738 sec
4. 0.42 sec

37: Let Pi and Pj    be two processes, R be the set of variables read from memory, ot and W be the set variables written to memory. For the concurrent execution of two processes Pi and Pj, which of the following conditions is not true?
1. R(Pi) ∩ W (Pj) = Φ
2. W(Pi) ∩ R (Pj) = Φ
3. R(Pi) ∩ R (Pj) = Φ
4. W(Pi) ∩ W (Pj) = Φ

38: A LRU page replacement is used with four page frames and eight pages. How many page faults will occur with the reference string 0172327103 if the four frames are initially empty?
1. 6
2. 7
3. 5
4. 8

39: What does the following command do ?
grep − vn  "abc" x
1. It will print all of the lines in the file x that match the search string "abc"
2. It will print all of the lines in file x that do not match the search string "abc"
3. It will print total no of the lines in file x that match the search string "abc".
4. It will print the specific line numbers of file x in which there is a match for the string "abc".

40: The Unix Kernel maintains two key data strucfures related to processes, the progress table and the user structure. Which of following information is not the part of user
1. File descriptor table
2. System call state
3. Scheduling parameters
4. Kernel stack

41: Match the following

 List - I List - II (a) Size-oriented metric (i) uses number of external interfaces as one of the measurement parameters (b) Function-oriented metrics (ii) originally designed to be applied to business information system (c) Extended Function Point Metrics (iii) derived by normalizing quality and/ or productivity measures by considering the size of the software. (d) Function Point (iv) uses algorithm characteristics as of the measurement parameter

(a)  (b)  (c)  (d)
1. (iii)  (iv)  (i)   (ii)
2. (ii)  (i)  (iv)   (iii)
3. (iv)  (ii)  (iii)   (i)
4. (iii)  (i)  (iv)   (ii)

42: In which testing strategy requirements established during requirements analysis are validated against developed software?
1. Validation testing
2. Integration testing
3. Regression testing
4. System testing

43: Which process model is also called as classic life cycle model?
1. Waterfall model
2. RAD model
3. Prototyping  model
4. Incremental model

44: Cohesion is an extension of :
1. Abstraction concept
2. Refinement concept
3. Information hiding concept (Software Engineering by R. Pressman Page No. 237)
4. Modularity

45: Which one from the following is highly associated activity of project planning?
1. Keep track of the project
2. Compare actual and planned progress and costs
3. Identify the activities, milestones and deliverables produced by a project
4. Both (2) and (3)

46: In the case of parallelization, Amdahl's law states that if P is the proportion of the program that can be made parallel and (1 - P) is the proportion that cannot be parallelized , then the maximum speed that can be achieved by using N processors is -
1. 1 / (1 - P) + N.P
2. 1 / (N – 1) P + P
3. 1 / (1 – P) + P / N
4. 1 / P + (1 – P) / N

47: Which of the following statements is incorrect for Parallel Virtual Machine (PVM)?
1. The PVM Communication model provides asynchronous blocking send, asynchronous blocking receive and non-blocking receive function
2. Message buffers are allocated dynamically
3. The PVM communication model assumes that any task that can send a message to any other PVM task and that there is no limit to the size or number of such messages
4. In PVM Model, the message order is not preserved

48: Which of the following algorithms sort n integers, having the range 0 to (n2 - 1), in ascending order in O(n) time ?
1. Selection sort
2. Bubble sort
3. Radix sort
4. Insertion sort

49: Which of the following statements is FALSE about weak entity set ?
1. Weak entities can be deleted. automatically when their strong entity is deleted.
2. Weak entity set avoids the data duplication and consequent possible inconsistencies caused by duplicating the key of the strong entity
3. A weak entity set has no primary keys unless attributes of the strong entity set on which it depends are included
4. Tuples in a weak enfity set are not partitioned according to their relationship with tuples in a strong entity set.

50: Which of the following is not valid with reference to Message Passing Interface (MPI) ?
1. MPI can run on any hardware platform
2. The programming model is a distributed memory model.
3. All parallelism is implicit
4. MPI - Comm - Size returns the total number of MPI processes in specified communication.

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