## UGC NET CS 2016 July- paper-2

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Question 1 |

How many different equivalence relations with exactly three different equivalence classes are there on a set with five elements?

10 | |

15 | |

25 | |

30 |

Question 1 Explanation:

Step-1: Given number of equivalence classes with 5 elements with three elements in each class will be 1,2,2 (or) 2,1,2 (or) 2,2,1 and 3,1,1.

Step-2: The number of combinations for three equivalence classes are

2,2,1 chosen in (

3,1,1 chosen in(

Step-3: Total differential classes are 15+10

=25.

Step-2: The number of combinations for three equivalence classes are

2,2,1 chosen in (

^{5}C_{ 2} *^{ 3} C_{2} *^{ 1} C_{ 1} )/2! = 153,1,1 chosen in(

^{5}C_{ 2} *^{ 3} C_{2} *^{ 1} C_{ 1} )/2! = 10Step-3: Total differential classes are 15+10

=25.

Question 2 |

The number of different spanning trees in complete graph, K

_{4} and bipartite graph, K_{2,2} have ______ and _______ respectively.14, 14 | |

16, 14 | |

16, 4 | |

14, 4 |

Question 2 Explanation:

Step-1: Given complete graph K 4 .To find total number of spanning tree in complete graph using standard formula is n

=n

= 4

=16

Step-2: Given Bipartite graph K

m=2 and n=2

= 2

= 2 * 2

= 4

^{(n-2)}Here, n=4=n

^{(n-2)}= 4

^{ 2}=16

Step-2: Given Bipartite graph K

_{ 2,2} . To find number of spanning tree in a bipartite graph K_{m,n} having standard formula is m^{ (n-1)} * n^{ (m-1)} .m=2 and n=2

= 2

^{(2-1)} * 2^{ (2-1)}= 2 * 2

= 4

Question 3 |

Suppose that R

_{1} and R_{ 2} are reflexive relations on a set A. Which of the following statements is correct ?R _{1} ∩ R_{ 2} is reflexive and R_{ 1} ∪ R_{ 2} is irreflexive. | |

R _{1} ∩ R_{ 2} is irreflexive and R_{ 1} ∪ R_{ 2} is reflexive. | |

Both R _{1} ∩ R_{ 2} and R_{ 1} ∪ R_{ 2} are reflexive. | |

Both R _{1} ∩ R_{ 2} and R_{ 1} ∪ R_{ 2} are irreflexive. |

Question 3 Explanation:

A binary relation R over a set X is reflexive if every element of X is related to itself. Formally, this may be written ∀ x ∈X : xRx.

Ex: Let set A={0,1}

R

R

R

R

Ex: Let set A={0,1}

R

_{1} ={(0,0),(1,1)} all diagonal elements we are considering for reflexive relation.R

_{2}={(0,0),(1,1)} all diagonal elements we are considering for reflexive relation.R

_{ 1} ∩ R_{ 2} must have {(0,0),(1,1)} is reflexive.R

_{1} ∪ R_{ 2} must have {(0,0),(1,1)} is reflexive.Question 4 |

There are three cards in a box. Both sides of one card are black, both sides of one card are red, and the third card has one black side and one red side. We pick a card at random and observe only one side.
What is the probability that the opposite side is the same colour as the one side we observed?

3/4 | |

2/3 | |

1/2 | |

1⁄3 |

Question 4 Explanation:

Given data,

-- 3 cards in a box

-- 1 st card: Both sides of one card is black. The card having 2 sides. We can write it as BB.

-- 2 nd card: Both sides of one card is red. The card having 2 sides. We can write it as RR.

-- 3rd card: one black side and one red side. We can write it as BR.

Step-1: The probability that the opposite side is the same colour as the one side we observed is 2⁄3 because total number of cards are 3

-- 3 cards in a box

-- 1 st card: Both sides of one card is black. The card having 2 sides. We can write it as BB.

-- 2 nd card: Both sides of one card is red. The card having 2 sides. We can write it as RR.

-- 3rd card: one black side and one red side. We can write it as BR.

Step-1: The probability that the opposite side is the same colour as the one side we observed is 2⁄3 because total number of cards are 3

Question 5 |

A clique in a simple undirected graph is a complete subgraph that is not contained in any larger complete subgraph. How many cliques are there in the graph shown below?

2 | |

4 | |

5 | |

6 |

Question 5 Explanation:

Definition of clique is already given in question.

Definition: A clique in a simple undirected graph is a complete subgraph that is not contained in any larger complete subgraph.

Step-1: b,c,e,f is complete graph.

Step-2: ‘a’ is not connected to ‘e’ and ‘b’ is not connected to ‘d’. So, it is not complete graph.

Definition: A clique in a simple undirected graph is a complete subgraph that is not contained in any larger complete subgraph.

Step-1: b,c,e,f is complete graph.

Step-2: ‘a’ is not connected to ‘e’ and ‘b’ is not connected to ‘d’. So, it is not complete graph.

Question 6 |

Which of the following logic expressions is incorrect?

1 ⊕ 0 = 1 | |

1 ⊕ 1 ⊕ 1 = 1 | |

1 ⊕ 1 ⊕ 0 = 1 | |

1 ⊕ 1 = 0 |

Question 6 Explanation:

Here, ⊕ is nothing but Ex-OR operator. The truth table for Ex-OR is

According to truth table,

Option-A is TRUE

Option-B is a 1 ⊕ 1 is 0.

0 ⊕ 1 is 1(TRUE)

Option-C is 1 ⊕ 1 is 0.

0 ⊕ 0 = 0 but given 1. So, FALSE

Option-D is TRUE.

According to truth table,

Option-A is TRUE

Option-B is a 1 ⊕ 1 is 0.

0 ⊕ 1 is 1(TRUE)

Option-C is 1 ⊕ 1 is 0.

0 ⊕ 0 = 0 but given 1. So, FALSE

Option-D is TRUE.

Question 7 |

The IEEE-754 double-precision format to represent floating point numbers, has a length of _____ bits.

16 | |

32 | |

48 | |

64 |

Question 7 Explanation:

→ The IEEE-754 double-precision format to represent floating point numbers has a length of 64 bits

→ In the IEEE 754-2008 standard, the 64-bit base-2 format is officially referred to as binary64 called double in IEEE 754-1985.

→ IEEE 754 specifies additional floating-point formats, including 32-bit base-2 single precision and, more recently, base-10 representations.

→ In the IEEE 754-2008 standard, the 64-bit base-2 format is officially referred to as binary64 called double in IEEE 754-1985.

→ IEEE 754 specifies additional floating-point formats, including 32-bit base-2 single precision and, more recently, base-10 representations.

Question 8 |

Simplified Boolean equation for the following truth table is:

F = yz’ + y’z | |

F = xy’ + x’y | |

F = x’z + xz’ | |

F = x’z + xz’ + xyz |

Question 8 Explanation:

Method-1: Using K-Map

Method-2: Using boolean simplification

= x’y’z+x’yz+xy’z’+xyz’

= x'z(y'+y)+ xz'(y'+y)

= x'z+xz' (Since y'+y=1)

Method-2: Using boolean simplification

= x’y’z+x’yz+xy’z’+xyz’

= x'z(y'+y)+ xz'(y'+y)

= x'z+xz' (Since y'+y=1)

Question 9 |

The simplified form of a Boolean equation (AB’ + AB’C + AC) (A’C’ + B’) is :

AB’ | |

AB’C | |

A’B | |

ABC |

Question 9 Explanation:

(AB’ + AB’C + AC) (A’C’ + B’)

= (AB'+AC) (A'C'+B')

= AB'A'C' + AB'B' + ACA'C' + ACB'

= AB'B' + ACB'

= AB'(C+1)

= AB'

= (AB'+AC) (A'C'+B')

= AB'A'C' + AB'B' + ACA'C' + ACB'

= AB'B' + ACB'

= AB'(C+1)

= AB'

Question 10 |

In a positive-edge-triggered JK flip-flop, if J and K both are high then the output will be _____ on the rising edge of the clock.

No change | |

Set | |

Reset | |

Toggle |

Question 10 Explanation:

__Positive-edge-triggered JK flip-flop is__

__The Truth Table for the JK Function__

When J = 1 and K = 1 , The output continuously Toggles from 1 to 0 and 0 to 1. At the end Output is indeterminate. This condition is called as Race around Condition. This happens when Propagation Delay is less than the Pulse width.

Question 11 |

Given i = 0, j = 1, k = –1 x = 0.5, y = 0.0 What is the output of the following expression in C language ?

x * y < i + j || k

x * y < i + j || k

-1 | |

0 | |

1 | |

2 |

Question 11 Explanation:

x * y < i + j || k

Step-1: Evaluate x * y because multiplication has more priority than remaining operators

x * y→ 0

Step-2: i + j is 1

Step-3: (x*y) < (i+j) is 1. Because relational operators only return 1(TRUE) or 0(FALSE).

Step-4: ((x*y) < (i+j)) || k is logical OR operator.

1 || -1 will returns 1.

Note: The precedence is ((x*y) < (i+j)) || k

Step-1: Evaluate x * y because multiplication has more priority than remaining operators

x * y→ 0

Step-2: i + j is 1

Step-3: (x*y) < (i+j) is 1. Because relational operators only return 1(TRUE) or 0(FALSE).

Step-4: ((x*y) < (i+j)) || k is logical OR operator.

1 || -1 will returns 1.

Note: The precedence is ((x*y) < (i+j)) || k

Question 12 |

The following statement in ‘C’

int (*f())[ ];

declares

int (*f())[ ];

declares

a function returning a pointer to an array of integers. | |

a function returning an array of pointers to integers. | |

array of functions returning pointers to integers. | |

an illegal statement. |

Question 12 Explanation:

int (*f())[ ] declare a function returning a pointer to an array of integers.

Question 13 |

Which one of the following is correct, when a class grants friend status to another class?

The member functions of the class generating friendship can access the members of the friend class. | |

All member functions of the class granted friendship have unrestricted access to the members of the class granting the friendship. | |

Class friendship is reciprocal to each other. | |

There is no such concept. |

Question 13 Explanation:

→ When a class grants friend status to another class all member functions of the class granted friendship have unrestricted access to the members of the class granting the friendship.

→ Although the entire second class must be a friend to the first class, you can select which functions in the first class will be friends of the second class.

→ Although the entire second class must be a friend to the first class, you can select which functions in the first class will be friends of the second class.

Question 14 |

When a method in a subclass has the same name and type signatures as a method in the super class, then the method in the subclass _____ the method in the super class.

Overloads | |

Friendships | |

Inherits | |

Overrides |

Question 14 Explanation:

→ When a method in a subclass has the same name and type signatures as a method in the superclass, then the method in the subclass overrides the method in the superclass.

Question 15 |

What is the value returned by the function f given below when n = 100?

int f (int n)

{

if (n = = 0) then return n;

else return n + f(n-2);

}

int f (int n)

{

if (n = = 0) then return n;

else return n + f(n-2);

}

2550 | |

2556 | |

5220 | |

5520 |

Question 15 Explanation:

Given n=100

Step-1: int f(100)

{ if (100 = = 0) then return 100; /*false*/

else return 100 + f(100-2); /* return 198 */

}

Step-2: int f(98)

{ if (98 = = 0) then return 98; /*false*/

else return 98 + f(96); /* return 194 */

}

Step-3: int f(96)

{ if (96 = = 0) then return 96; /*false*/

else return 96 + f(94); /* return 190 */

}

;

;

Step-final:

int f(0)

{ if (0 = = 0) then return 0; /*TRUE*/

else return 0 + f(0); /* FALSE */

}

Actual process:

The above series is nothing but sum of Arithmetic Progression(A.P)

= 2+4+6+8+ ... +98+100

= n(n+1)

/* It is nothing but sum of even numbers upto 'n' */

= 50*51

= 2550

Step-1: int f(100)

{ if (100 = = 0) then return 100; /*false*/

else return 100 + f(100-2); /* return 198 */

}

Step-2: int f(98)

{ if (98 = = 0) then return 98; /*false*/

else return 98 + f(96); /* return 194 */

}

Step-3: int f(96)

{ if (96 = = 0) then return 96; /*false*/

else return 96 + f(94); /* return 190 */

}

;

;

Step-final:

int f(0)

{ if (0 = = 0) then return 0; /*TRUE*/

else return 0 + f(0); /* FALSE */

}

Actual process:

The above series is nothing but sum of Arithmetic Progression(A.P)

= 2+4+6+8+ ... +98+100

= n(n+1)

/* It is nothing but sum of even numbers upto 'n' */

= 50*51

= 2550

Question 16 |

In RDBMS, the constraint that no key attribute (column) may be NULL is referred to as:

Referential integrity | |

Multi-valued dependency | |

Entity Integrity | |

Functional dependency |

Question 16 Explanation:

→ The constraint that no key attribute (column) may be NULL is referred to as Entity Integrity.

→ Referential integrity to hold in a relational database, any column in a base table that is declared a foreign key can only contain either null values or values from a parent table's primary key or a candidate key.

→ A multivalued dependency exists when there are at least three attributes (like X,Y and Z) in a relation and for a value of X there is a well defined set of values of Y and a well defined set of values of Z. However, the set of values of Y is independent of set Z and vice versa.

→ A functional dependency is a constraint between two sets of attributes in a relation from a database. In other words, functional dependency is a constraint that describes the relationship between attributes in a relation.

→ Referential integrity to hold in a relational database, any column in a base table that is declared a foreign key can only contain either null values or values from a parent table's primary key or a candidate key.

→ A multivalued dependency exists when there are at least three attributes (like X,Y and Z) in a relation and for a value of X there is a well defined set of values of Y and a well defined set of values of Z. However, the set of values of Y is independent of set Z and vice versa.

→ A functional dependency is a constraint between two sets of attributes in a relation from a database. In other words, functional dependency is a constraint that describes the relationship between attributes in a relation.

Question 17 |

Which of the following statement(s) is/are FALSE in the context of Relational DBMS ?

I. Views in a database system are important because they help with access control by allowing users to see only a particular subset of the data in the database.

II. E-R diagrams are useful to logically model concepts.

III. An update anomaly is when it is not possible to store information unless some other, unrelated information is stored as well.

IV. SQL is a procedural language.

I. Views in a database system are important because they help with access control by allowing users to see only a particular subset of the data in the database.

II. E-R diagrams are useful to logically model concepts.

III. An update anomaly is when it is not possible to store information unless some other, unrelated information is stored as well.

IV. SQL is a procedural language.

I and IV only | |

III and IV only | |

I, II and III only | |

II, III and IV only |

Question 17 Explanation:

Statement-I is TRUE because a VIEW of a table allows you to display updated version of the particular subset of the data in a database. A VIEW is a virtual table based on the result set of SQL
statement.

Statement-II is FALSE because E-R diagram useful to Conceptually model concepts.

Statement-III is FALSE because update anomaly is a data inconsistency results from partial update or data redundancy.

Statement-IV is FALSE because SQL is not a procedural language. A language is procedural when we call procedures( like functions, subroutine) but in SQL we don't do any such calls.

Statement-II is FALSE because E-R diagram useful to Conceptually model concepts.

Statement-III is FALSE because update anomaly is a data inconsistency results from partial update or data redundancy.

Statement-IV is FALSE because SQL is not a procedural language. A language is procedural when we call procedures( like functions, subroutine) but in SQL we don't do any such calls.

Question 18 |

In a relational database model, NULL values can be used for all but which one of the following ?

To allow duplicate tuples in the table by filling the primary key column(s) with NULL. | |

To avoid confusion with actual legitimate data values like 0 (zero) for integer columns and ’’ (the empty string) for string columns. | |

To leave columns in a tuple marked as ’’unknown’’ when the actual value is unknown. | |

To fill a column in a tuple when that column does not really ”exist” for that particular tuple. |

Question 18 Explanation:

→ NULL values are used in a relation when the value of column of a particular row is either Unknown or does Not Exist.

→ Sometimes the a column of a row does not contain any value or may have zero value in that case also NULL values are used to avoid any kind of confusion regarding the values of the column. So, Option (B),(C) and (D) are the cases when NULL values are used in a relation.

Option(A) is incorrect because Primary key of a relation is a key which uniquely identify each tuple of a relation so it can't have NULL values.

→ Sometimes the a column of a row does not contain any value or may have zero value in that case also NULL values are used to avoid any kind of confusion regarding the values of the column. So, Option (B),(C) and (D) are the cases when NULL values are used in a relation.

Option(A) is incorrect because Primary key of a relation is a key which uniquely identify each tuple of a relation so it can't have NULL values.

Question 19 |

Consider the following two commands C1 and C2 on the relation R from an SQL database:

C1 : drop table R;

C2 : delete from R;

Which of the following statements is TRUE ?

I. Both C1 and C2 delete the schema for R.

II. C2 retains relation R, but deletes all tuples in R.

III. C1 deletes not only all tuples of R, but also the schema for R.

C1 : drop table R;

C2 : delete from R;

Which of the following statements is TRUE ?

I. Both C1 and C2 delete the schema for R.

II. C2 retains relation R, but deletes all tuples in R.

III. C1 deletes not only all tuples of R, but also the schema for R.

I only | |

I and II only | |

II and III only | |

I, II and III |

Question 19 Explanation:

→ Dropping the relation means to delete the content of a table and free up the space allocated to a table.

→ Deleting the tuples means keeping the space allocated to a table/relation but deleting the data relation contains.

→ Now DELETE command is used to delete the tuples of a relation while DROP command is used to delete the schema as well as tuples of a relation.

Hence option (C) is correct.

→ Deleting the tuples means keeping the space allocated to a table/relation but deleting the data relation contains.

→ Now DELETE command is used to delete the tuples of a relation while DROP command is used to delete the schema as well as tuples of a relation.

Hence option (C) is correct.

Question 20 |

Consider the following database table having A, B, C and D as its four attributes and four possible candidate keys (I, II,III and IV) for this table :

I : {B}

II : {B, C}

III : {A, D}

IV : {C, D}

If different symbols stand for different values in the table (e.g., d1 is definitely not equal to d2 ), then which of the above could not be the candidate key for the database table ?

I : {B}

II : {B, C}

III : {A, D}

IV : {C, D}

If different symbols stand for different values in the table (e.g., d1 is definitely not equal to d2 ), then which of the above could not be the candidate key for the database table ?

I and III only | |

III and IV only | |

II only | |

I only |

Question 20 Explanation:

→Given table will find that attribute {B},{A,D},{C,D} can uniquely identify each tuple of the given table.

→ So, we can say that {B},{A,D},{C,D} are the candidate keys of the given relation. And we know that a candidate key is a minimal key using which each tuple of a relation can be uniquely identified And the super set of a candidate key is a Super Key instead of candidate Key.

→ Since {B} is a candidate key so {B,C} is a Super Key, not the Candidate key of the given relation.

→ So, the key which can't be the candidate key of given relation is {B,C}.

→ So, we can say that {B},{A,D},{C,D} are the candidate keys of the given relation. And we know that a candidate key is a minimal key using which each tuple of a relation can be uniquely identified And the super set of a candidate key is a Super Key instead of candidate Key.

→ Since {B} is a candidate key so {B,C} is a Super Key, not the Candidate key of the given relation.

→ So, the key which can't be the candidate key of given relation is {B,C}.

Question 21 |

Consider the following binary search tree:

If we remove the root node, which of the node from the left subtree will be the new root?

If we remove the root node, which of the node from the left subtree will be the new root?

11 | |

12 | |

13 | |

16 |

Question 21 Explanation:

Usually binary search tree follows inorder. When we are using inorder automatically, the elements are in sorted order. There are worst case also, elements are not in sorted order.

After removing root element, binary search tree is looks like

After removing root element, binary search tree is looks like

Question 22 |

Consider the following operations performed on a stack of size 5 :
Push (a); Pop() ; Push(b); Push(c); Pop();
Push(d); Pop();Pop(); Push (e)
Which of the following statements is correct?

Underflow occurs | |

Stack operations are performed smoothly | |

Overflow occurs | |

None of the above |

Question 22 Explanation:

Here, stack size is 5. Stack operations are explained in step by step.

Question 23 |

Suppose you are given a binary tree with n nodes, such that each node has exactly either zero or two children. The maximum height of the tree will be

(n/2) -1 | |

(n/2) +1 | |

(n–1) / 2 | |

(n+1) / 2 |

Question 23 Explanation:

→ They are given definition of full binary tree. The full binary tree each node has exactly either zero or two children.

→ The maximum height of the tree will be (n–1) / 2. It is standard property of full binary tree.

→ The maximum height of the tree will be (n–1) / 2. It is standard property of full binary tree.

Question 24 |

Which of the following is not an inherent application of stack?

Implementation of recursion | |

Evaluation of a postfix expression | |

Job scheduling | |

Reverse a string |

Question 24 Explanation:

Applications

1. Implementation of recursion

2. Evaluation of a postfix expression

3. Expression evaluation and syntax parsing

4. Backtracking

5. Compile time memory management

6. Reverse a string

1. Implementation of recursion

2. Evaluation of a postfix expression

3. Expression evaluation and syntax parsing

4. Backtracking

5. Compile time memory management

6. Reverse a string

Question 25 |

In how many ways can the string
A ∩ B – A ∩ B – A
be fully parenthesized to yield an infix expression?

15 | |

14 | |

13 | |

12 |

Question 25 Explanation:

In this problem look very difficult to solve, but problem is following standard formula only.

Step-1: Total number of letters/operands with duplication is 5.

Step-3: To find total number of ways, we have catalan formula.

Here, n=5

Catalan number = (2n)! / (n! * (n+1)!)

= (2*5)! / (5! * (5+1)!)

= 10! / (5! * 6!)

= 14

Note: We used catalan formula because they given in fully parenthesized to yield an infix expression.

Step-1: Total number of letters/operands with duplication is 5.

Step-3: To find total number of ways, we have catalan formula.

Here, n=5

Catalan number = (2n)! / (n! * (n+1)!)

= (2*5)! / (5! * (5+1)!)

= 10! / (5! * 6!)

= 14

Note: We used catalan formula because they given in fully parenthesized to yield an infix expression.

Question 26 |

A multiplexer combines four 100-Kbps channels using a time slot of 2 bits. What is the bit rate?

100 Kbps | |

200 Kbps | |

400 Kbps | |

1000 Kbps |

Question 26 Explanation:

Frame duration= 1/50,000

= 20 sec

Frame size= No.of bits per frame

= 8 bits

Bit Rate= Frame Rate * No.of bits per frame

= 50000*8

= 400 kbps

= 20 sec

Frame size= No.of bits per frame

= 8 bits

Bit Rate= Frame Rate * No.of bits per frame

= 50000*8

= 400 kbps

Question 27 |

In a fully-connected mesh network with 10 computers, total ______ number of cables are required and ______ number of ports are required for each device.

40,9 | |

45,10 | |

45,9 | |

50,10 |

Question 27 Explanation:

Fully connected mesh network, it means it is complete graph. We have standard formula to find total number of cables.

Here, n=10(total number of computers)

= n(n-1) / 2

= 10(9) / 2

= 45

→ To accommodate that many links, every device on the network must have n-1 input/output(I/O) ports

n=10(total number of computers)

= n-1 ports

= 10-1

= 9

Here, n=10(total number of computers)

= n(n-1) / 2

= 10(9) / 2

= 45

→ To accommodate that many links, every device on the network must have n-1 input/output(I/O) ports

n=10(total number of computers)

= n-1 ports

= 10-1

= 9

Question 28 |

In TCP/IP Reference model, the job of _______ layer is to permit hosts to inject packets into any network and travel them independently to the destination.

Physical | |

Transport | |

Application | |

Host-to-network | |

None of the above |

Question 29 |

If there are N people in the world and are using secret key encryption/decryption for privacy purpose, then number of secret keys required will be:

N | |

(N - 1) | |

N(N - 1) / 2 | |

N(N + 1) / 2 |

Question 29 Explanation:

→ If there are N people in the world and are using secret key encryption/decryption for privacy purpose, then number of secret keys required will be N(N-1) / 2.

→ To communicate using symmetric cryptography, both parties have to agree on a secret key. After that, each message is encrypted with that key, transmitted, and decrypted with the same key. Key distribution must be secret. If it is compromised, messages can be decrypted and users can be impersonated. However, if a separate key is used for each pair of users, the total number of keys increases rapidly as the number of users increases. With n users, we would need [n(n-1)]/2 keys.

→ To communicate using symmetric cryptography, both parties have to agree on a secret key. After that, each message is encrypted with that key, transmitted, and decrypted with the same key. Key distribution must be secret. If it is compromised, messages can be decrypted and users can be impersonated. However, if a separate key is used for each pair of users, the total number of keys increases rapidly as the number of users increases. With n users, we would need [n(n-1)]/2 keys.

Question 30 |

Optical fiber uses reflection to guide light through a channel, in which angle of incidence is ________ the critical angle.

equal to | |

less than | |

greater than | |

less than or equal to |

Question 30 Explanation:

→ Optical fiber uses reflection to guide light through a channel, in which angle of incidence is greater than the critical angle.

→ Total internal reflection is the phenomenon which occurs when a propagated wave strikes a medium boundary at an angle larger than a particular critical angle with respect to the normal to the surface.

→ If the refractive index is lower on the other side of the boundary and the incident angle is greater than the critical angle, the wave cannot pass through and is entirely reflected.

→ Total internal reflection is the phenomenon which occurs when a propagated wave strikes a medium boundary at an angle larger than a particular critical angle with respect to the normal to the surface.

→ If the refractive index is lower on the other side of the boundary and the incident angle is greater than the critical angle, the wave cannot pass through and is entirely reflected.

Question 31 |

The number of strings of length 4 that are generated by the regular expression (0|∈)1 + 2* (3|∈), where | is an alternation character, {+, *} are quantification characters, and ∈ is the null string, is :

08 | |

10 | |

11 | |

12 |

Question 31 Explanation:

Possible strings of length 4 generated by given regular expression are:

1111, 0111, 1112, 0122, 0123, 1222, 1223, 0122, 0113, 1123, 0112, 1113.

So, total 12 strings of length 4 are possible.

1111, 0111, 1112, 0122, 0123, 1222, 1223, 0122, 0113, 1123, 0112, 1113.

So, total 12 strings of length 4 are possible.

Question 32 |

The content of the accumulator after the execution of the following 8085 assembly language program, is:
MVI A, 42H
MVI B, 05H
UGC: ADD B
DCR B
JNZ UGC
ADI 25H
HLT

82 H | |

78 H | |

76 H | |

47 H |

Question 32 Explanation:

Step-1: MVI A, 42H given 42 value in hexadecimal and storing value in Accumulator A.

For solving problem, convert (42)

Step-2: MVI B, 05H given 05 value in hexadecimal and storing value in Accumulator B.

For solving problem, convert (05)

Step-3: ADD B until UGC will fail. Contents of accumulator A value and B value will add.

66+5=71

Step-4: DCR B it means decrement by 1.

71+4=75

Step-5: JNZ means jump not equals to zero.

75+3=78

78+2=80

80+1=81

Step-6: It became false, then execute next statement.

ADI 25H means add 25H to (81)

(25)

37+81=(118)

Finally

convert decimal value into Hexadecimal.

(118)

Step-7: HLT means halt the program.

Note: We are converting hexadecimal into decimal for only calculation. without conversion also we can solve a problem.

For solving problem, convert (42)

_{16} into decimal is (66)_{10}Step-2: MVI B, 05H given 05 value in hexadecimal and storing value in Accumulator B.

For solving problem, convert (05)

_{16} into decimal is (05)_{10}Step-3: ADD B until UGC will fail. Contents of accumulator A value and B value will add.

66+5=71

Step-4: DCR B it means decrement by 1.

71+4=75

Step-5: JNZ means jump not equals to zero.

75+3=78

78+2=80

80+1=81

Step-6: It became false, then execute next statement.

ADI 25H means add 25H to (81)

_{ 10}(25)

_{16} = (37)_{ 10}37+81=(118)

_{ 10}Finally

convert decimal value into Hexadecimal.

(118)

_{10} = (76)_{ 16}Step-7: HLT means halt the program.

Note: We are converting hexadecimal into decimal for only calculation. without conversion also we can solve a problem.

Question 33 |

In _______, the bodies of the two loops are merged together to form a single loop provided that they do not make any references to each other.

Loop unrolling | |

Strength reduction | |

Loop concatenation | |

Loop jamming |

Question 33 Explanation:

Loop Unrolling: Loop unrolling refers to method of decreasing the number of time a loop is executed.

Strength reduction: It is a machine independent code optimization technique in which a costly operation(operation which takes more time to execute) is replaced with the cheaper. operation(operation which takes less execution time)

Loop Jamming: It is a loop optimization technique in which bodies of two loops are combined together to decrease the number of loops.

Strength reduction: It is a machine independent code optimization technique in which a costly operation(operation which takes more time to execute) is replaced with the cheaper. operation(operation which takes less execution time)

Loop Jamming: It is a loop optimization technique in which bodies of two loops are combined together to decrease the number of loops.

Question 34 |

Which of the following is not typically a benefit of dynamic linking?

I. Reduction in overall program execution time.

II. Reduction in overall space consumption in memory.

III. Reduction in overall space consumption on disk.

IV. Reduction in the cost of software updates.

I. Reduction in overall program execution time.

II. Reduction in overall space consumption in memory.

III. Reduction in overall space consumption on disk.

IV. Reduction in the cost of software updates.

I and IV | |

I only | |

II and III | |

IV only |

Question 34 Explanation:

TRUE: Reduction in overall program execution time.

FALSE: Reduction in overall space consumption in memory.

FALSE: Reduction in overall space consumption on disk.

FALSE: Reduction in the cost of software updates.

Note: Except statement-I remaining all statements are not related to dynamic linking.

FALSE: Reduction in overall space consumption in memory.

FALSE: Reduction in overall space consumption on disk.

FALSE: Reduction in the cost of software updates.

Note: Except statement-I remaining all statements are not related to dynamic linking.

Question 35 |

Which of the following is FALSE?

The grammar S → a Sb |bSa|SS|∈, where S is the only non-terminal symbol and ∈ is the null string, is ambiguous. | |

SLR is powerful than LALR. | |

An LL(1) parser is a top-down parser. | |

YACC tool is an LALR(1) parser generator. |

Question 35 Explanation:

A grammar is said to be ambiguous if and only if it can generate parse trees of both Left Most Derivation or Right Most Derivation.

In this grammar we are having two different parse trees For string "aabb" using leftmost derivation only.

Statement B is wrong because in LALR we use lookahead symbols to put the reduce entries into the parsing table. Because of which number of blank entries in LALR parser are more than that of SLR parser which in turn increases the error detection capability of LALR parser. So LALR parser is more powerful than SLR.

Statement C is true because LL(1) parser is a top-down parser

Statement D is also true because YACC(Yet Another Compiler Compiler) is a tool which generates LALR parser for a given grammar.

In this grammar we are having two different parse trees For string "aabb" using leftmost derivation only.

Statement B is wrong because in LALR we use lookahead symbols to put the reduce entries into the parsing table. Because of which number of blank entries in LALR parser are more than that of SLR parser which in turn increases the error detection capability of LALR parser. So LALR parser is more powerful than SLR.

Statement C is true because LL(1) parser is a top-down parser

Statement D is also true because YACC(Yet Another Compiler Compiler) is a tool which generates LALR parser for a given grammar.

Question 36 |

Consider the reference string

0 1 2 3 0 1 4 0 1 2 3 4

If FIFO page replacement algorithm is used, then the number of page faults with three page frames and four page frames are _______ and ______ respectively.

0 1 2 3 0 1 4 0 1 2 3 4

If FIFO page replacement algorithm is used, then the number of page faults with three page frames and four page frames are _______ and ______ respectively.

10, 9 | |

9, 9 | |

10, 10 | |

9,10 |

Question 36 Explanation:

FIFO page replacement algorithm with 3 page frames

FIFO page replacement algorithm with 3 page frames

FIFO page replacement algorithm with 3 page frames

Question 37 |

Suppose there are four processes in execution with 12 instances of a Resource R in a system.
The maximum need of each process and current allocation are given below:
With reference to current allocation, is system safe ? If so, what is the safe sequence ?

No | |

Yes, P _{1} P_{ 2} P_{ 3} P_{ 4} | |

Yes, P _{4} P_{ 3} P_{ 1} P_{ 2} | |

Yes, P _{2} P_{ 1} P_{ 3} P_{ 4} |

Question 37 Explanation:

Step-1: Current allocation for all processors are 3+4+2+1=10.

Step-2: Given total number of resources is 12. But we already allocated 12-10=2.

It means 2 resources are free. we can call M=2

Step-3: P4 requires 2 free resources. Total free resources are 2. So, we can allocate for P4.

Then M become M=3

Step-4: P3 requires 2 free resources. Total free resources are 2. So, we can allocate for P3.

Then M become M=5

Step-5: P1 requires 5 free resources. Total free resources are 5. So, we can allocate for P1.

Then M become M=8

Step-5: P2 requires 5 free resources. Total free resources are 8. So, we can allocate for P2.

Then M become M=12

Note: We have alternative possibility is P4,P3,P2,P1.

Step-2: Given total number of resources is 12. But we already allocated 12-10=2.

It means 2 resources are free. we can call M=2

Step-3: P4 requires 2 free resources. Total free resources are 2. So, we can allocate for P4.

Then M become M=3

Step-4: P3 requires 2 free resources. Total free resources are 2. So, we can allocate for P3.

Then M become M=5

Step-5: P1 requires 5 free resources. Total free resources are 5. So, we can allocate for P1.

Then M become M=8

Step-5: P2 requires 5 free resources. Total free resources are 8. So, we can allocate for P2.

Then M become M=12

Note: We have alternative possibility is P4,P3,P2,P1.

Question 38 |

If the Disk head is located initially at track 32, find the number of disk moves required with FCFS scheduling criteria if the disk queue of I/O blocks requests are:
98, 37, 14, 124, 65, 67

320 | |

322 | |

321 | |

319 |

Question 38 Explanation:

Question 39 |

In UNIX, _________ creates three subdirectories : ‘PIS’ and two subdirectories ‘progs’ and ‘data’ from just created subdirectory ‘PIS’.

mkdir PIS/progs PIS/data PIS | |

mkdir PIS progs data | |

mkdir PIS PIS/progs PIS/data | |

mkdir PIS/progs data |

Question 39 Explanation:

mkdir→ Will make new directory

PIS → It is directory name

PIS/progs → PIS directory having subdirectory is “prog”

PIS/data → PIS directory having subdirectory is “data”

mkdir PIS PIS/progs PIS/data will creates three subdirectories :

‘PIS’ and two subdirectories ‘progs’ and ‘data’ from just created subdirectory ‘PIS’.

PIS → It is directory name

PIS/progs → PIS directory having subdirectory is “prog”

PIS/data → PIS directory having subdirectory is “data”

mkdir PIS PIS/progs PIS/data will creates three subdirectories :

‘PIS’ and two subdirectories ‘progs’ and ‘data’ from just created subdirectory ‘PIS’.

Question 40 |

A scheduling Algorithm assigns priority proportional to the waiting time of a process. Every process starts with priority zero (lowest priority). The scheduler reevaluates the process priority for every ‘T’ time units and decides next process to be scheduled. If the process have no I/O operations and all arrive at time zero, then the scheduler implements _________ criteria.

Priority scheduling | |

Round Robin Scheduling | |

Shortest Job First | |

FCFS |

Question 40 Explanation:

→ A scheduling Algorithm assigns priority proportional to the waiting time of a process. Every process starts with priority zero (lowest priority). The scheduler reevaluates the process priority for
every ‘T’ time units and decides next process to be scheduled. If the process have no I/O operations and all arrive at time zero, then the scheduler implements Round Robin criteria.

Round Robin Scheduling: → To schedule processes fairly, a round-robin scheduler generally employs time-sharing, giving each job a time slot or quantum(its allowance of CPU time), and interrupting the job if it is not completed by then. The job is resumed next time a time slot is assigned to that process. If the process terminates or changes its state to waiting during its attributed time quantum, the scheduler selects the first process in the ready queue to execute.

→ Round-robin algorithm is a pre-emptive algorithm as the scheduler forces the process out of the CPU once the time quota expires.

Round Robin Scheduling: → To schedule processes fairly, a round-robin scheduler generally employs time-sharing, giving each job a time slot or quantum(its allowance of CPU time), and interrupting the job if it is not completed by then. The job is resumed next time a time slot is assigned to that process. If the process terminates or changes its state to waiting during its attributed time quantum, the scheduler selects the first process in the ready queue to execute.

→ Round-robin algorithm is a pre-emptive algorithm as the scheduler forces the process out of the CPU once the time quota expires.

Question 41 |

If S 1 is total number of modules defined in the program architecture, S 3 is the number of modules whose correct function depends on prior processing then the number of modules not dependent on prior processing is :

1 + (S _{3} / S_{ 1} ) | |

1 - (S _{3} / S_{ 1} ) | |

1 + (S _{1} / S_{ 3} ) | |

1 - (S _{1} / S_{ 3} ) |

Question 41 Explanation:

S1 = The total number of modules defined in the program architecture.

S3 = The number of modules whose correct function depends on prior processing.

Module not dependent on prior processing is 1- (S3/S1)

S3 = The number of modules whose correct function depends on prior processing.

Module not dependent on prior processing is 1- (S3/S1)

Question 42 |

The ________ model is preferred for software development when the requirements are not clear.

Rapid Application Development | |

Rational Unified Process | |

Evolutionary Model | |

Waterfall Model |

Question 42 Explanation:

→ Rapid Application Development(RAD) is used when the requirements cannot or will not be specified.

→ Evolutionary Model is preferred for software development when the requirements are not clear.

→ The evolutionary software process model, is more commonly known as the “spiral model”.

→ Evolutionary Model is preferred for software development when the requirements are not clear.

→ The evolutionary software process model, is more commonly known as the “spiral model”.

Question 43 |

Which of the following is not included in waterfall model?

Requirement analysis | |

Risk analysis | |

Design | |

Coding |

Question 43 Explanation:

Waterfall model steps:

1.Feasibility Study

2.Analysis

3.Design

4.Coding and Testing

5.Integration & System testing

6.Maintenance

1.Feasibility Study

2.Analysis

3.Design

4.Coding and Testing

5.Integration & System testing

6.Maintenance

Question 44 |

The cyclomatic complexity of a flow graph V(G), in terms of predicate nodes is: [Where P is number of predicate nodes in flow graph V(G).]

P + 1 | |

P – 1 | |

P – 2 | |

P + 2 |

Question 44 Explanation:

There are 3 formulas to find cyclomatic complexity.
1. The number of regions corresponds to the cyclomatic complexity

2. V(G),Flow graph is defined as V(G)=E-N+2 where E is the number of flow graph edges, and N is the number of flow graph nodes.

3. V(G),Flow graph is defined as V(G)=P+1 where p is the number of predicate nodes contained in the flow graph G.

2. V(G),Flow graph is defined as V(G)=E-N+2 where E is the number of flow graph edges, and N is the number of flow graph nodes.

3. V(G),Flow graph is defined as V(G)=P+1 where p is the number of predicate nodes contained in the flow graph G.

Question 45 |

The extent to which a software tolerates the unexpected problems, is termed as:

Accuracy | |

Reliability | |

Correctness | |

Robustness |

Question 45 Explanation:

→ The extent to which a software tolerates the unexpected problems is termed as Robustness.

→ Robustness is the ability of a computer system to cope with errors during execution and cope with erroneous input.

→ Accuracy is a description of systematic errors, a measure of statistical bias.

→ Software reliability is the probability that software will work properly in a specified environment and for a given amount of time.

→ Correctness of an algorithm is asserted when it is said that the algorithm is correct with respect to a specification. Functional correctness refers to the input-output behaviour of the algorithm (i.e., for each input it produces the expected output).

→ Robustness is the ability of a computer system to cope with errors during execution and cope with erroneous input.

→ Accuracy is a description of systematic errors, a measure of statistical bias.

→ Software reliability is the probability that software will work properly in a specified environment and for a given amount of time.

→ Correctness of an algorithm is asserted when it is said that the algorithm is correct with respect to a specification. Functional correctness refers to the input-output behaviour of the algorithm (i.e., for each input it produces the expected output).

Question 46 |

An attacker sits between customer and Banker, and captures the information from the customer and retransmits to the banker by altering the information. This attack is called as ______.

Masquerade Attack | |

Replay Attack | |

Passive Attack | |

Denial of Service Attack |

Question 46 Explanation:

→ A masquerade takes place when one entity pretends to be a different entity. A masquerade attack usually includes one of the other forms of active attack. For example,authentication sequences can be captured and replayed after a valid authentication sequence has taken place, thus enabling an authorized entity with few privileges to obtain extra privileges by impersonating an entity that has those privileges.

→ Replay involves the passive capture of a data unit and its subsequent retransmission to produce an unauthorized effect.

→ Passive attacks are very difficult to detect, because they do not involve any alteration of the data.Typically,the message traffic is sent and received in an apparently normal fashion,and neither the sender nor receiver is aware that a third party has read the messages or observed the traffic pattern.However,it is feasible to prevent the success of these attacks,usually by means of encryption.Thus,the emphasis in dealing with passive attacks is on prevention rather than detection.

→ The denial of service prevents or inhibits the normal use or management of communications facilities.This attack may have a specific target; for example, an entity may suppress all messages directed to a particular destination (e.g.,the security audit service).Another form of service denial is the disruption of an entire network,either by disabling the network or by overloading it with messages so as to degrade performance

→ Replay involves the passive capture of a data unit and its subsequent retransmission to produce an unauthorized effect.

→ Passive attacks are very difficult to detect, because they do not involve any alteration of the data.Typically,the message traffic is sent and received in an apparently normal fashion,and neither the sender nor receiver is aware that a third party has read the messages or observed the traffic pattern.However,it is feasible to prevent the success of these attacks,usually by means of encryption.Thus,the emphasis in dealing with passive attacks is on prevention rather than detection.

→ The denial of service prevents or inhibits the normal use or management of communications facilities.This attack may have a specific target; for example, an entity may suppress all messages directed to a particular destination (e.g.,the security audit service).Another form of service denial is the disruption of an entire network,either by disabling the network or by overloading it with messages so as to degrade performance

Question 47 |

Consider the following two statements :

(A) Business intelligence and Data warehousing is used for forecasting and Data mining.

(B) Business intelligence and Data warehousing is used for analysis of large volumes of sales data.

Which one of the following options is correct ?

(A) Business intelligence and Data warehousing is used for forecasting and Data mining.

(B) Business intelligence and Data warehousing is used for analysis of large volumes of sales data.

Which one of the following options is correct ?

(A) is true, (B) is false. | |

Both (A) and (B) are true. | |

(A) is false, (B) is true. | |

Both (A) and (B) are false. |

Question 47 Explanation:

TRUE: Business intelligence and Data warehousing is used for forecasting and Data mining.

TRUE: Business intelligence and Data warehousing is used for analysis of large volumes of sales data.

TRUE: Business intelligence and Data warehousing is used for analysis of large volumes of sales data.

Question 48 |

Pipelining improves performance by:

decreasing instruction latency | |

eliminating data hazards | |

exploiting instruction level parallelism | |

decreasing the cache miss rate |

Question 48 Explanation:

→ Pipelining improves performance by exploiting instruction level parallelism.

→ Instruction pipelining is a technique for implementing instruction-level parallelism within a single processor.

→ Pipelining attempts to keep every part of the processor busy with some instruction by dividing incoming instructions into a series of sequential steps (the eponymous "pipeline") performed by different processor units with different parts of instructions processed in parallel.

→ It allows faster CPU throughput than would otherwise be possible at a given clock rate, but may increase latency due to the added overhead of the pipelining process itself.

→ Instruction pipelining is a technique for implementing instruction-level parallelism within a single processor.

→ Pipelining attempts to keep every part of the processor busy with some instruction by dividing incoming instructions into a series of sequential steps (the eponymous "pipeline") performed by different processor units with different parts of instructions processed in parallel.

→ It allows faster CPU throughput than would otherwise be possible at a given clock rate, but may increase latency due to the added overhead of the pipelining process itself.

Question 49 |

Consider the following two statements :

(A) Data scrubling is a process to upgrade the quality of data, before it is moved into Data warehouse.

(B) Data scrubling is a process of rejecting data from data warehouse to create indexes.

Which one of the following options is correct ?

(A) Data scrubling is a process to upgrade the quality of data, before it is moved into Data warehouse.

(B) Data scrubling is a process of rejecting data from data warehouse to create indexes.

Which one of the following options is correct ?

(A) is true, (B) is false. | |

(A) is false, (B) is true. | |

Both (A) and (B) are false. | |

Both (A) and (B) are true. |

Question 49 Explanation:

→ Data scrubbing is an error correction technique that uses a background task to periodically inspect main memory or storage for errors, then correct detected errors using redundant data in the form of different checksums or copies of data.

→ Data scrubbing reduces the likelihood that single correctable errors will accumulate, leading to reduced risks of uncorrectable errors.

→ Data scrubbing reduces the likelihood that single correctable errors will accumulate, leading to reduced risks of uncorrectable errors.

Question 50 |

Given the following statements:

(A) Strategic value of data mining is timestamping.

(B) Information collection is an expensive process in building an expert system.

Which of the following options is correct?

(A) Strategic value of data mining is timestamping.

(B) Information collection is an expensive process in building an expert system.

Which of the following options is correct?

Both (A) and (B) are false. | |

Both (A) and (B) are true. | |

(A) is true, (B) is false. | |

(A) is false, (B) is true. |

Question 50 Explanation:

TRUE: Strategic value of data mining is timestamping.

TRUE: Information collection is an expensive process in building an expert system.

→ An expert system is a computer system that emulates the decision making ability of a human expert.

TRUE: Information collection is an expensive process in building an expert system.

→ An expert system is a computer system that emulates the decision making ability of a human expert.

There are 50 questions to complete.