Saturday, 12 May 2018


Solved Paper II UGC NET Computer Science November 2017
1.

 If the time is now 4 O'clock, what will be the time after 101 hours from now?
(1) 9 O'clock
(2) 8 O'clock
(3) 5 O'clock
(4) 4 O'clock
Answer: 1
Explanation:
After 24 hours , time will again be 4 O'clock. 
101%24 = 5 
Hence time after 101 hours will be 4+5=9 o'clock
2.       Let m = (313)4 and n = (322)4. Find the base 4 expansion of m + n.
(1) (635)4
(2) (32312)4
(3) (21323)4
(4) (1301)4
Answer: 4
Explanation:
m = (313)4 and n = (322)4
Convert m and n to decimal.
m = 3*4^2 + 1*4^1 + 3*4^0 = 48+4+3 = (55)10
m = 3*4^2 + 2*4^1 + 2*4^0 = 48+8+2 = (58)10
m+n = 55+58 = 113
Now we have to convert 113 to base 4.
113%4 = 1 ---(1)
113/4 = 28
28%4 = 0 ---(2)
28/4 = 7
7%4 = 3 ----(3)
7/4 = 1
1%4 = 1 ----(4)
The answer will be step(4) to step (1) = 1301
3.       Let 
Find the boolean product AʘB of the two matrices. 
 

Answer: 1
Explanation:
We can only multiply two matrices if the number of columns in the first matrix is the same as the number of rows in the second matrix.
So the boolean product AB =

So option (1) is the correct answer.
4.       How many distinguishable permutations of the letters in the word BANANA are there?
(1) 720
(2) 120
(3) 60
(4) 360
Answer: 3
 
Explanation:
Number of permutation of n objects with n1 identical objects of type 1, n2 identical objects of type 2, ..........and nk identical objects of type k is n! / n1!n2!....nk!

Here, first we have to count the total number of letters in it. Here it is 6.

Find out how many letters are repeating in the word. Here A is repeated 3 times. N is repeated 2 times.


So, Permutation of letter BANANA are 6! / 3!2! = 60
5.       Consider the graph given below :

Use Kruskal's algorithm to find a minimal spanning tree for the graph. The List of the edges of the tree in the order in which they are chosen is?
(1) AD, AE, AG, GC, GB, BF
(2) GC, GB, BF, GA, AD, AE
(3) GC, AD, GB, GA, BF, AE
(4) AD, AG, GC, AE, GB, BF
Answer: Marks to all
 
Explanation:
Kruskal’s Algorithm builds the spanning tree by adding edges one by one into a growing spanning tree. Kruskal's algorithm follows greedy approach as in each iteration it finds an edge which has least weight and add it to the growing spanning tree. 

Algorithm Steps:
* Sort the graph edges with respect to their weights.
* Start adding edges to the MST from the edge with the smallest weight until the edge of the largest weight.

* Only add edges which doesn't form a cycle , edges which connect only disconnected components.
Here all options (1), (2), (3) and (4) are matching with minimum spanning tree.
6.       The Boolean function with the Karnaugh map
is :
(1) (A + C).D + B
(2) (A + B).C + D
(3) (A + D).C + B
(4) (A + C).B + D
Answer: 1
Explanation:
From the above Karnaugh map, we will get B + CD + AD.
It can be reduced as (A+C).D+B
7.       The Octal equivalent of the binary number 1011101011 is:
(1) 7353
(2) 1353
(3) 5651
(4) 5657
Answer: 2
 
Explanation:
Group all the bits in the binary number in sets of three, starting from the far right. Add zeros to the left of the last digit if you don't have enough digits to make a set of three.
Original Binary: 1011101011
Grouping: 1  011  101  011
Adding Zeros for Groups of Three: 001  011  101  011
001=1, 011=3, 101=5, 011=3
So final answer will be 1353
 
8.       Let P and Q be two propositions, ⌐(P ↔ Q) is equivalent to:
(1) P ↔ ⌐ Q
(2) ⌐P↔ Q
(3) ⌐P↔ ⌐Q
(4) Q → P
Answer: 1, 2
Explanation:

P
Q
¬P
¬Q
Q → P
⌐(P ↔ Q)
P ↔ ⌐ Q
⌐P↔ Q
⌐P↔ ⌐Q
0
0
1
1
1
0
0
0
1
0
1
1
0
0
1
1
1
0
1
0
0
1
1
1
1
1
0
1
1
0
0
1
0
0
0
1
So both options 1 and 2 are correct.

Important Logical Equivalences.

The logical equivalences below are important equivalences that should be memorized.
Identity Laws:
p ∧ T ⇔ p
p ∨ F ⇔ p
Domination Laws:
p ∨ T ⇔ T
p ∧ F ⇔ F
Idempotent Laws:
p ∨ p ⇔ p
p ∧ p ⇔ p
Double Negation Law:
¬(¬p) ⇔ p
Commutative Laws:
p ∨ q ⇔ q ∨ p
p ∧ q ⇔ q ∧ p
Associative Laws:
(p ∨ q) ∨ r ⇔ p ∨ (q ∨ r)
(p ∧ q) ∧ r ⇔ p ∧ (q ∧ r)
Distributive Laws:
p ∨ (q ∧ r) ⇔ (p ∨ q) ∧ (p ∨ r)
p ∧ (q ∨ r) ⇔ (p ∧ q) ∨ (p ∧ r)
De Morgan’s Laws:
¬(p ∧ q) ⇔ ¬p ∨ ¬q
¬(p ∨ q) ⇔ ¬p ∧ ¬q
Absorption Laws:
p ∧ (p ∨ q) ⇔ p
p ∨ (p ∧ q) ⇔ p
Implication Law:
(p → q) ⇔ (¬p ∨ q)
Contrapositive Law:
(p → q) ⇔ (¬q → ¬p)
Tautology:
p ∨ ¬p ⇔ T
Contradiction:
p ∧ ¬p ⇔ F
Equivalence:
(p → q) ∧ (q → p) ⇔ (p ↔ q)
9.       Negation of the proposition Ǝ x H(x) is:
(1) Ǝ x ⌐H(x)
(2) x ⌐H(x)
(3) x H(x)
(4) ⌐ x H(x)
Answer: 2
 
10.    The output of the following combinational circuit is F.
The value of F is :
(1) P1+P2’P3
(2) P1+P2’P3
(3) P1+P2P3
(4) P1’+P2P3
Answer: 2
The value of F is :
(1) P1+P2’P3
(2) P1+P2’P3
(3) P1+P2P3
(4) P1’+P2P3
Answer: 2

11.       'ptrdata'  is a pointer to a data type. The expression *ptrdata++ is evaluated as (in C++):
(1) *(ptrdata++)
(2) (*ptrdata++)
(3) *(ptrdata)++
(4) Depends on compiler
Answer: 1
 
12.       The associativity of which of the following operators is Left to Right, in C++?
(1) Unary Operator
(2) Logical not
(3) Array element access
(4) addressof
Answer: 3
CategoryOperatorAssociativity
Postfix() [] -> . ++ - -Left to right
Unary + - ! ~ ++ - - (type)* & sizeofRight to left
Multiplicative* / %Left to right
Additive+ -Left to right
Shift<< >>Left to right
Relational<  <=  >  >=Left to right
Equality==  !=Left to right
Bitwise AND&Left to right
Bitwise XOR^Left to right
Bitwise OR|Left to right
Logical AND&&Left to right
Logical OR||Left to right
Conditional?: Right to left
Assignment =  +=  -=  *=  /=  %=  >>=  <<=  &=  ^=  |=Right to left
Comma,Left to right
 
 
13.       A member function can always access the data in ................ , (in C++).
(1) the class of which it is member
(2) the object of which it is a member
(3) the public part of its class
(4) the private part of its class
Answer: 1
 
14.       Which of the following is not correct for virtual function in C++?
(1) Must be declared in public section of class.
(2) Virtual function can be static.
(3) Virtual function should be accessed using pointers.
(4) Virtual function is defined in base class.
Answer: 2
 
15.       Which of the following is not correct (in C++)?
(1) Class templates and function templates are instantiated in the same way.
(2) Class templates differ from function templates in the way they are initiated.
(3) Class template is initiated by defining an object using the template argument.
(4) Class templates are generally used for storage classes.
Answer: 2,3,4

16.       Which of the following is/are true with reference to 'view' in DBMS?
(a) A 'view' is a special stored procedure executed when certain event occurs.
(b) A 'view' is a virtual table, which occurs after executing a pre-compiled query.
Code:
(1) Only (a) is true
(2) Only (b) is true
(3) Both (a) and (b) are true
(4) Neither (a) nor (b) are true
Answer: 2
 
17.       In SQL, .................. is an Aggregate function.
(1) SELECT
(2) CREATE
(3) AVG
(4) MODIFY
Answer: 3
 
18.       Match the following with respect to RDBMS:
List - I
(a) Entity integrity
(b) Domain integrity
(c) Referential integrity
(d) Userdefined integrity
List - II
(i) enforces some specific business rule that do not fall into entity or domain
(ii) Rows can't be deleted which are used by other records
(iii) enforces valid entries for a column
(iv) No duplicate rows in a table
Code:
     (a)   (b)   (c)  (d)
(1) (iii)  (iv)  (i)   (ii)
(2) (iv)  (iii)  (ii)   (i)
(3) (iv)  (ii)   (iii)  (i)
(4) (ii)   (iii)  (iv)  (i)
Answer: 2
 
19.       In RDBMS, different classes of relations are created using ................... technique to prevent modification anomalies.
(1) Functional Dependencies
(2) Data integrity
(3) Referential integrity
(4) Normal Forms
Answer: 4
20.    .................. SQL command changes one or more fields in a record.
(1) LOOK-UP
(2) INSERT
(3) MODIFY
(4) CHANGE
Answer: 3

21.       Consider an array representation of an n element binary heap where the elements are stored from index 1 to index n of the array. For the element stored at index i of the array (i< = n), the index of the parent is:
(1) floor ((i +1)/2)
(2) ceiling ((i + 1)/2)
(3) floor (i/2)
(4) ceiling (i/2)
Answer: 3
 Explaination:
A binary heap is a heap data structure that takes the form of a binary tree. Binary heaps are a common way of implementing priority queues.
A heap is a Tree which satisfies the following two properties:
1. All the child nodes must be less (or greater) than its parent node for a min (or max) heap.
2. The leaves must either fill the h or h-1 node where h is the height of the tree; it means it must be a complete binary tree.
 
22.       The following numbers are inserted into an empty binary search tree in the given order:
10, 1, 3, 5, 15, 12, 16. What is the height of the binary search tree?
(1) 3
(2) 4
(3) 5
(4) 6
Answer: 1
 
The height is the maximum distance of a leaf node from the root
Constructed binary search tree will be..
                    10
                  /     \
                 1       15
                 \      /  \
                  3    12   16
                    \
                     5
 
 
23.       Let G be an undirected connected graph with distinct edge weight. Let Emax be the edge with maximum weight and Emin the edge with minimum weight. Which of the following statements is false?
(1) Every minimum spanning tree of G must contain Emin.
(2) If Emax is in minimum spanning tree, then its removal must disconnect G.
(3) No minimum spanning tree contains Emax.
(4) G has a unique minimum spanning tree.
Answer: 3
 
24.       A list of n strings, each of length n, is sorted into lexicographic order using merge - sort algorithm. The worst case running time of this computation is:
(1) O(n log n)
(2) O(n2 log n)
(3) O(n2 + log n)
(4) O(n3)
Answer: 2
 
25.       Postorder traversal of a given binary search tree T produces following sequence of keys:
3, 5, 7, 9, 4, 17, 16, 20, 18, 15, 14
Which one of the following sequences of keys can be the result of an in-order traversal of the tree T?
(1) 3, 4, 5, 7, 9, 14, 20, 18, 17, 16, 15
(2) 20, 18, 17, 16, 15, 14, 3, 4, 5, 7, 9
(3) 20, 18, 17, 16, 15, 14, 9, 7, 5, 4, 3
(4) 3, 4, 5, 7, 9, 14, 15, 16, 17, 18, 20
Answer: 4
 Explanation: Inorder traversal of a BST always gives elements in increasing order. Among all four options, 4 ) is the only increasing order sequence.

26.       Which of the following devices takes data sent from one network device and forwards it to the destination node based on MAC address?
(1) Hub
(2) Modem
(3) Switch
(4) Gateway
Answer: 3
 
27.       .................. do not take their decisions on measurements or estimates of the current traffic and topology.
(1) Static algorithms
(2) Adaptive algorithms
(3) Non - adaptive algorithms
(4) Recursive algorithms
Answer: 3
 
28.       The number of bits used for addressing in Gigabit Ethernet is ...................
(1) 32 bits
(2) 48 bits
(3) 64 bits
(4) 128 bits
Answer: 2
 
29.       Which of the following layer of OSI Reference model is also called end-to-end layer?
(1) Network layer
(2) Datalink layer
(3) Session layer
(4) Transport layer
Answer: 4
 
30.    The IP address ................... is used by hosts when they are being booted.
(1) 0.0.0.0
(2) 1.0.0.0
(3) 1.1.1.1
(4) 255.255.255.255
Answer: 1
 

31.       Consider the following program fragment in assembly language:
    mov ax, 0h
    mov cx, 0A h
doloop:
    dec ax
    loop doloop
What is the value of ax and cx registers after the completion of the doloop?
(1) ax = FFF5 h and cx = 0 h
(2) ax = FFF6 h and cx = 0 h
(3) ax = FFF7 h and cx = 0A h
(4) ax = FFF5 h and cx = 0A h
Answer: 2
 
32.       Consider the following assembly program segment:
stc
mov al, 11010110b
mov cl, 2
rcl al, 3
rol al, 4
shr al, cl
mul cl
The contents of the destination register ax (in hexadecimal) and the status of Carry Flag (CF) after the execution of above instructions are:
(1) ax = 003CH; CF = 0
(2) ax = 001EH; CF = 0
(3) ax = 007BH; CF = 1
(4) ax = 00B7H; CF = 1
Answer: 1
 
33.       Which of the following regular expressions, each describing a language of binary numbers (MSB to LSB) that represents non-negative decimal values, does not include even values?
(1) 0*1+0*1*
(2) 0*1*0+1*
(3) 0*1*0*1+
(4) 0+1*0*1*
Where {+, *} are quantification characters.
Answer: 3
 
34.       Which of the following statements is/ are TRUE?
(a) The grammar S → SS a is ambiguous. (Where S is the start symbol)
(b) The grammar S → 0S1 | 01S | ϵ is ambiguous. (The special symbol ϵ represents the empty string) (Where S is the start symbol)
(c) The grammar (Where S is the start symbol)
S → T/U
T → x S y | xy | ϵ
U → yT
generates a language consisting of the string yxxyy.
(1) Only (a) and (b) are TRUE.
(2) Only (a) and (c) are TRUE.
(3) Only (b) and (c) are TRUE.
(4) All of (a), (b) and (c) are TRUE.
Answer: 4
 
35.       Match the description of several parts of a classic optimizing compiler in List - I, with the names of those parts in List - II:
List - I
(a) A part of a compiler that is responsible for recognizing syntax.
(b) A part of a compiler that takes as input a stream of characters and produces as output a stream of words along with their associated syntactic categories.
(c) A part of a compiler that understand the meanings of variable names and other symbols and checks that they are used in ways consistent with their definitions.
(d) An IR-to-IR transformer that tries to improve the IR program in some way (Intermediate representation).
List - II
(i) Optimizer
(ii) Semantic Analysis
(iii) Parser
(iv) Scanner
Code:
      (a) (b) (c) (d)
(1) (iii) (iv) (i) (ii)
(2) (iv) (iii) (ii) (i)
(3) (ii) (iv) (i) (iii)
(4) (ii) (iv) (iii) (i)
Answer: 1
 

36.       In Distributed system, the capacity of a system to adapt the increased service load is called .................
(1) Tolerance
(2) Scalability
(3) Capability
(4) Loading
Answer: 2
 
37.       In .................... disk scheduling algorithm, the disk head moves from one end to other end of the disk, serving the requests along the way. When the head reaches the other end, it immediately returns to the beginning of the disk without serving any requests on the return trip.
(1) LOOK
(2) SCAN
(3) C - LOOK
(4) C - SCAN
Answer: 4
Explaination:
 
In operating systems, seek time is very important. Since all device requests are linked in queues, the seek time is increased causing the system to slow down. Disk Scheduling Algorithms are used to reduce the total seek time of any request.  
 
38.       Suppose there are six files F1, F2, F3, F4, F5, F6 with corresponding sizes 150 KB, 225KB, 75 KB, 60 KB, 275 KB and 65 KB respectively. The files are to be stored on a sequential device in such a way that optimizes access time. In what order should the files be stored?
(1) F5, F2, F1, F3, F6, F4
(2) F4, F6, F3, F1, F2, F5
(3) F1, F2, F3, F4, F5, F6
(4) F6, F5, F4, F3, F2, F1
Answer: 2
 F4      F6     F3    F1     F2     F4
 60      65     75    150   225    275
Explanation: For access time optimization sort the files in increasing order of file size.
So, option (2) is correct.
 
 
39.       Which module gives control of the CPU to the process selected by the short - term scheduler?
(1) Dispatcher
(2) Interrupt
(3) Scheduler
(4) Threading
Answer: 1
 
Explaination:- 
The dispatcher is the module that gives control of the CPU to the process selected by the short-time scheduler(selects from among the processes that are ready to execute).
  The function involves :
  Swithching context
  Switching to user mode
  Jumping to the proper location in the user program to restart that program.
 
 
40.    Two atomic operations permissible on Semaphores are .................. and ...............
(1) wait, stop
(2) wait, hold
(3) hold, signal
(4) wait, signal
Answer: 4

41.       Software does not wear-out in the traditional sense of the term, but software does tend to deteriorate as it evolves, because:
(1) Software suffers from exposure to hostile environments.
(2) Defects are more likely to arise after software has been used often.
(3) Multiple change requests introduce errors in component interactions.
(4) Software spare parts become harder to order.
Answer: 3
 
42.       Software re-engineering is concerned with:
(1) Re-constructing the original source code from the existing machine (low - level) code program and modifying it to make it more user - friendly.
(2) Scrapping the source code of a software and re-writing it entirely from scratch.
(3) Re-organising and modifying existing software systems to make them more maintainable.
(4) Translating source code of an existing software to a new machine (low - level) language.
Answer: 3
 
43.       Which of the following is not a key issue stressed by an agile philosophy of software engineering?
(1) The importance of self-organizing teams as well as communication and collaboration between team members and customers.
(2) Recognition that change represents opportunity.
(3) Emphasis on rapid delivery of software that satisfies the customer.
(4) Having a separate testing phase after a build phase.
Answer: 4
 
44.       What is the normal order of activities in which traditional software testing is organized?
(a) Integration Testing
(b) System Testing
(c) Unit Testing
(d) Validation Testing
Code:
(1) (c), (a), (b), (d)
(2) (c), (a), (d), (b)
(3) (d), (c), (b), (a)
(4) (b), (d), (a), (c)
Answer: 2
 
45.       Which of the following testing techniques ensures that the software product runs correctly after the changes during maintenance?
(1) Path Testing
(2) Integration Testing
(3) Unit Testing
(4) Regression Testing
Answer: 4
 

46.       Which of the following Super Computers is the fastest Super Computer?
(1) Sun-way TaihuLight
(2) Titan
(3) Piz Daint
(4) Sequoia
Answer: 1
 
47.       Which of the following statements about ERP system is true?
(1) Most ERP software implementations fully achieve seamless integration.
(2) ERP software packages are themselves combinations of seperate applications for manufacturing, materials, resource planning, general ledger, human resources, procurement and order entry.
(3) Integration of ERP systems can be achieved in only one way.
(4) An ERP package implemented uniformly throughout an enterprise is likely to contain very flexible connections to allow charges and software variations.
Answer: 2
48.       Which of the following is not a Clustering method?
(1) K - Mean method
(2) Self Organizing feature map method
(3) K - nearest neighbour method
(4) Agglomerative method
Answer: 3
 
49.       Which of the given wireless technologies used in IoT, consumes the least amount of power?
(1) Zigbee
(2) Bluetooth
(3) Wi-Fi
(4) GSM/CDMA
Answer: 2
 
50.    Which speed up could be achieved according to Amdahl's Law for infinite number of processes if 5% of a program is sequential and the remaining part is ideally parallel?
(1) Infinite
(2) 5
(3) 20
(4) 50
Answer: 3
Explanation: According to Amdahl’s law speed up for infinite number of process:
 S = 1 / (1-P) 
where p is parallel part of program
Given, sequential part of program is 5%. So parallel part of the program (P)
= 1 - sequential part
= 1 - 0.05 (or 5%)
= 0.95 (or 95%)

Now S = 1 / (1-P)
ie  S = 1 / (1-0.95)
    S = 1 / 0.05
    S = 20 
So, option (3) is correct.

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