UGC NET June-2019 CS Paper-2

Question 1
How many are there to place 8 indistinguishable balls into four distinguishable bins?
A
70
B
165
C
8​ C​ 4
D
8​ P​ 4T
Question 1 Explanation: 
This is precisely the problem we saw to solve the r-combination with repetition:
= C(8+4-1,8)
= 11 C​ 8
= 11! / (8!(11-8)!)
= 165
Question 2
Match List-I with List-II:
List-I                                                                          List-II
(Software process Models)                             (Software System)
(a) Waterfall model                        (i) e-business that starts with only the basic functionality and then moves on to more advanced
                                                                  features.
(b) Incremental development       (ii) An inventory control system for a supermarket to be developed in a highway
(c) Prototyping                              (iii) A virtual reality system for simulating vehicle navigation in a highway.
(d) RAD                              (iv) Automate the manual system for student record maintenance in a school
Choose the correct option from those given below:
A
(a)-(ii),(b)-(iv),(c)-(i),(d)-(iii)
B
(a)-(i),(b)-(iii),(c)-(iv),(d)-(ii)
C
(a)-(iii),(b)-(ii),(c)-(iv),(d)-(i)
D
(a)-(iv),(b)-(i),(c)-(iii),(d)-(ii)
Question 2 Explanation: 
Waterfall model→ Automate the manual system for student record maintenance in a school
Incremental development→ e-business that starts with only the basic functionality and then moves on to more advanced features.
Prototyping→ A virtual reality system for simulating vehicle navigation in a highway.
RAD→ An inventory control system for a supermarket to be developed in a highway
Question 3
A computer has six tapes drives with n processes competing for them. Each process may need two drives. What is the maximum value of n for the system to be deadlock free?
A
5
B
4
C
3
D
6
Question 3 Explanation: 
Each process needs 2 drives. So for deadlock just give each process one drive. So total 6 process can be given 1 drive each and can cause deadlock. So to break deadlock just reduce 1 process.
So maximum no. of process for the system to be deadlock free is 5.
Question 4
In the context of 3D computer graphics, which of the following statements is/are TRUE?
P: Orthographics transformations keep parallel lines parallel
Q: Orthographic transformations are affine transformations
Select the correct answer from the options given below:
A
Both P and Q
B
Neither P and Q
C
Only P
D
Only Q
Question 5
Which of the following statements are DMl statements?
(a) Update [tablename]
Set [ columnname] = VALUE
(b) Delete [tablename]
(c) Select * from [tablename]
A
(a) and (b)
B
(a) and (d)
C
(a), (b) and (c)
D
(b) and (c)
Question 5 Explanation: 
Question 6
What percentage(%) of the IPv4, IP address space do all class C addresses consume?
A
12.5%
B
25%
C
37.5%
D
50%
Question 6 Explanation: 
Total possible IP numbers numbers of all classes 0 to 255.
Class-A: 0 to 127. It means 50%
Class-B: 128 to 191. It means 25%
Class-C: 192 to 223. It means 12.5 %
Class-D: 224 to 239. It means 6.25%
Class-E: 240 to 255. It means 6.25%
Question 7
Which of the following key constraints is required for functioning of foreign key in the context of relational database?
A
Unique key
B
Primary key
C
candidate key
D
Check key
Question 7 Explanation: 
Foreign key is a key whose values depends on the primary key of a relation. So for the functioning of a foreign key in the context of relational database we need a primary key.
Question 8
Software Reuse is
A
The process of analysing software with the objective of recovering its design and specification
B
The process of existing software artifacts and knowledge to build new software
C
Concerned with reimplementing legacy system to make them more maintainable
D
The process of analysing software to create a representation of a higher level of abstraction and breaking software down into its parts to see how it works
Question 8 Explanation: 
Software Reuse is the process of existing software artifacts and knowledge to build new software.
Question 9
Which of the following is principal conjunctive normal form for [(pVq) ∧ ~p → ~q]?
A
pV~q
B
pVq
C
~p Vq
D
~p V ~q
Question 9 Explanation: 
Question 10
Match List-I with List-II
List-I                          List-II
(a) p → q                (i) ¬(q → ¬p)
(b) p v q                  (ii) p ∧ ¬q
(c) p ∧ q                  (iii) ¬p → q
(d) ¬(p → q)            (iv) ¬p v q
Choose the correct option from those given below:
A
(a)-(ii);(b)-(iii);(c)-(i);(d)-(iv)
B
(a)-(ii);(b)-(i);(c)-(iii);(d)-(iv)
C
(a)-(iv);(b)-(i);(c)-(iii);(d)-(ii)
D
(a)-(iv);(b)-(iii);(c)-(i);(d)-(ii)
Question 10 Explanation: 
Question 11
Consider the following methods:
M​ 1 ​ : mean of maximum
M​ 2​ : Centre of area
M​ 3​ : Height method
Which of the following is/are defuzzification method(s)?
A
Only M​ 1
B
Only M​ 1​ and M​ 2
C
Only M​ 2​and M​ 3
D
M​ 1​ , M​ 2​ and M​ 3
Question 11 Explanation: 
Defuzzication Methods: Following defuzzication methods are known to calculate crisp output → Maxima Methods
1.Height method
2.First of maxima (FoM)
3.Last of maxima (LoM)
4.Mean of maxima(MoM)
→ Centroid methods:
1. Center of gravity method (CoG)
2. Center of sum method (CoS)
3. Center of area method (CoA)
→ Weighted average method
Question 12
Replacing the expression 4*2.14 by 8.56 is known as
A
Constant folding
B
Induction variable
C
Strength reduction
D
Code reduction
Question 12 Explanation: 
Take variable i=4*2.14
We are simply folding the value into 8.56 because to avoid multiplication costly operation.
Question 13
A fuzzy conjunction operator denoted as t(x,y) and fuzzy disjunction operator denoted as s(x,Y) form dual pair if they satisfy the condition:
A
t(x,y)= 1-s(x,y)
B
t(x,y)=s(1-x,1-y)
C
t(x,y)=1-s(1-x,1-y)
D
t(x,y)=s(1+x,1+y)
Question 13 Explanation: 
Question 14
Which data structure is used by the compiler for managing variables and their attributes?
A
Binary tree
B
link list
C
Symbol table
D
Parse table
Question 14 Explanation: 
Symbol tables are data structures that are used by compilers to hold information about source-program constructs. The information is collected incrementally by the analysis phases of a compiler and used by the synthesis phases to generate the target code. Entries in the symbol table contains information about an identifier such as its character string (or lexeme) , its type,its position in storage, and any other relevant information.
Question 15
Which type of addressing mode, less number of memory references are required?
A
Immediate
B
Implied
C
register
D
indexed
E
None of the above
Question 15 Explanation: 
Excluded for evaluation
Question 16
How many different Boolean functions of degree n are there?
A
2​2n
B
(2​2​)​2
C
2​2n-1
D
2n
Question 16 Explanation: 
There are 2​ n​ different n-tuples of 0s and 1s.
A Boolean function is an assignment of 0 or 1 to each of these 2​ n​ different n-tuples.
Therefore, there are 2​ 2^n different Boolean functions.
Example: How many different Boolean functions of degree 4 are there?
Solution: 16
Question 17
Consider the equation (146)​ b​ + (313)​ b-2​ = (246)​ 8​ . Which of the following is the value of b?
A
8
B
7
C
10
D
16
Question 17 Explanation: 
(146)7+(317)7-2=(246)8
Substitute 7 in b,
(146)7+(317)7-2=(246)8
(146)7+(317)5=(246)8
(146)7=1*72+4*71+6*70
=49+28+6
=83
(317)5=3*52+1*51+7*50
=75+5+7
= 87
(246)8=2*82+4*81+6*80
=128+32+6
= 166
∴ (146)7+(317)5=(246)8
=83+87
=166
166=166
LHS = RHS equal only if b is 7.
Question 18
Match List-I with List-II
List-I                                  List-II
(a) Disk                         (i) Thread
(b) CPU                         (ii) Signal
(c) Memory                  (iii) File System
(d) Interrupt                 (iv) Virtual address
Choose the correct option from those given below:
A
(a)-(i); (b)-(ii); (c)-(iii); (d)-(iv)
B
(a)-(iii); (b)-(i); (c)-(iv); (d)-(ii)
C
(a)-(ii); (b)-(i); (c)-(iv); (d)-(iii)
D
(a)-(ii); (b)-(iv); (c)-(iii);(d)-(i)
Question 18 Explanation: 
Disk--> File system
CPU → Thread
memory → Virtual address space
Interrupt → Signal
Question 19
In the TCP/IP model, encryption and decryption are functions of ____ layer
A
data link
B