## UGC NET Computer Science Solved Paper -II June 2015

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 fish 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)|≥ l/2(n-1)(n-2)+ 2edges

(c) deg (v) + deg (w) ≥ n for every v and co 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 optimal 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 = l, y = 0 and C_{i }(carry input) = 0

(b) x = 0,y = l and C_{i} = l

Compute the values of S(sum) and C_{o}(carry output) for the above input values.

(1) S = l, C_{o} =0 and S= 0, C_{o}=l (2) S = 0,C_{o} =0 and S= l, C_{o} =1

(3) S = l, C_{o} = l and S= 0, C_{o}= 0 (4) S = 0,C_{o} = l and S= l, C_{o} = 0

8. “If my computations are correct and I pay the electric bill, then I will run out of money. If I don’t pay the electric bill, 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

Codes :

(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 *x ^{2}*≥ 25 and its proof as:

If x≥6, then

*x*= x.x≥6-6 = 36≥25

^{2}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 ()

{

charS[]=’ABCDEFGH”;

printf (“%C”, * (& S[3]));

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 = P1.0, n = 1.0, m = 2.0

thevalueofPPx I j==x>n> = mis:

(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 file-systems:

(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, it must be associated 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 Minimum Cost Spanning Tree is .

Ans: (2)

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 searched 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 statements

(4) Counting kilobytes of algorithm

*1*

*2*