June 2010 Paper II - Part 1

Introduction

The NET(National Eligibility Test) is executed on behalf of the University Grants Commission (UGC) to decide the eligibility of Indian nationals for the Eligibility of Assistant Professorship, Junior Research Fellowship, or both for Indian Colleges and Universities.

This article discusses the previous year's UGC-NET computer science questions of June 2010 Paper II. We will see these questions along with their answers and explanation.

Questions

1.“x1 is a clone of x” indicates x1 is identical to x in terms of physical attributes, namely, height, weight, and complexion. Given the height, weight, and complexion only form a complete set of attributes for an entity. Cloning is an equivalence relation. What is your impression of this statement?

Answer: A

Explanation: The statement says that the Relation R contains x and x1, identical. This means (x,x1) is the same as (x,x). We know that the relation of (x,x) type is an equivalence as it satisfies the Reflexive, symmetric, transitive conditions. Option A is correct; it is equivalence.

2. ‘R is a robot of M’, which means R can perform some of the tasks M would otherwise do, and R cannot do anything else. Which of the subsequent is the most appropriate representation to model this situation?

Answer: B

Explanation: Given R is a robot of M. 

Step-1: Constraint is that R can perform some tasks of M. This implies M can do all tasks. But sometimes, R can't do what they can do by M. 

Step-2: The above constraint represents that Mis superset and Ris subset of M. 

We can illustrate this in the Venn diagram as

3. “My Lafter Machin (MLM) recognizes the subsequent strings:

Using this as information, how would you compare the subsequent regular expressions?

Answer: D

Explanation: m is generating a single "a."

If you observe all of them are generating (aba)x

Note: This question is ambiguous. The wordings are not very clear.

4.

The chromatic number of a graph would be vertices of the actors/entities affected in the sentences S1 to S5 and edges to describe the associations/relationships amongst the entities/actors as described in the sentences S1 to S5 above?

(A) 2

(B) 3

(C) 4

(D) None of these

Answer: B

Explanation: It contains a triangle, so the chromatic number can not be less than 3.

5. You have a 4-decimal-digit secret personal code for an ATM debit card. In the absence of a clue, a brute-force attack takes time-‘t' to crack the code on an ATM terminal. Therefore 't' is the secure time for a customer to report if the card is misplaced. Your Bank has decided to encourage an increased secure time. Which option below should provide the largest rise in the value of 't'?

Answer: B

Explanation: To get the four-digit password, the possible number digit would be 104, which has a brute-force attack takes time-'t'. Therefore 't' is the secure time for a customer to Increase the security more time. The size of the password should increase by five digits or more.

6. The logic expression for the output of the circuit below is:

Answer: None

Explanation: [((A+B)'+C)' + (C+D)']' 

=((A+B)' + C)(C + D) 

=(A'B' + C)(C + D) 

=A'B'C + C + A'B'D + CD 

=(A'B' + 1 + D)C + A'B'D 

=A'B'D + C

Note: Wrong options has been given.

7. Advantage of the synchronous sequential circuits over the asynchronous ones is:

Answer: A

Explanation: A clock signal does not synchronize asynchronous sequential logic; the outputs of the circuit change directly in response to changes in inputs. The benefit of asynchronous logic is that it can be faster than synchronous logic since the circuit don't have to wait for a clock signal to process the inputs.

8. What is transitive voltage for the voltage input of a CMOS operating from a 10V supply?

(A) 1V

(B) 2V

(C) 5V

(D) 10 V

Answer: C

Explanation: The Threshold voltage is V_dd/2 if the input voltage is V_dd.

9. What is the decimal equivalent of BCD 11011.1100?

(A) 22.0

(B) 22.2

(C) 20.2

(D) 21.2

Answer: B

Explanation: BCD is a weighted Code which is 8421.

and BCD Code 0-9 digit only.

For, e.g., let's take N=12, now convert 12 into Binary which is (1100)2

now Convert N=12 into BCD(Binary Coded Decimal), 0001 0010.

So, how do we convert Binary no. to BCD: ADD 0110 into Binary Number

So 1100+0110=   10010  (make pair of 4 from right So 0001 0010 which is 12)

Now Move to the question:

given BCD is 11011.1100, make pair of 4. We see its range is not between 0-9. So we need to correct it by adding 0110 to the place where the range is not between 0-9.

0001 1011.1100 + 0000 0110.0110

= 0010 0010.0010

now make pair of 4, and we'll see 22.2

So, the answer is B.

10. The function illustrated by the kmap given below is

Answer: C

Explanation: 

11. The statement

will print

(A) 10

(B) 0

(C) 12

(D) 1

Answer: D

Explanation: We can write the above statement into (10? (0? 5:1):12) 

Step 1: (0 ? 5:1) - It will give result one because the condition is FALSE. After all, the given value is o. If nonzero is given in condition, it will print a TRUE value. 

Step 2: (10 ? 1:12) - The given condition is nonzero. So, it will print the TRUE value (i.e., 1). 

Note: Ternary operators(?:) starts evaluation from innermost conditions first.

12. What will be the output of the following C language code?

(A) a

(B) c

(C) b

(D) q

Answer: C

Explanation: Pointer "p" points to the string "ayqm", 

*p denotes the first character of a string, which is "a".

++*p represents an increment of "a," which is "b."

printf("%c", c); prints the character "b" as output.

Note: They gave syntax errors in the program.

13. Members of a class specified as…………… are accessible only to the method of the class.

(A) private

(B) public

(C) protected

(D) derive

Answer: A

Explanation: Members of the class specified as private are accessible only to the class method.

Private is the default for a class member if no access specifier is used.

When we pass an argument by call by value, a copy of the argument is made into the formal subroutine parameter, and changes made to the subroutine parameters do not affect the original argument. They remain the same.

14. Match the following:

Set-I

(a) Garbage collection in

(b) Nameless object

(c) Template support

(d) A forward reference

(e) Derived class inherits from base class

Set-II

1. Java

2. generic programming

3. defines a class

4. member function

5. within a statement

Codes :

(a) (b) (c) (d) (e)

(A) 1 5 4 2 3

(B) 1 5 2 3 4

(C) 5 1 2 3 4

(D) 5 4 3 1 2

Answer: B

Explanation: 

Garbage collection in -> Java 

Nameless object -> Within a statement

Template support -> Generic programming

A forward reference -> defines a class

A derived class inherits from base class -> Member function.

15. The data type made by the data abstraction process is called

Answer: C

Explanation: The data abstraction process's data type is called ADT(abstract data type). ADT is a category of objects whose logical behavior we define by values and a set of operations.

16. An entity instance is the single occurrence of an …………..

Answer: A

Explanation: The entity type is the heading or schema, and the entity instance is the value of the entity type at a particular instance. 

Example: PERSON(Age, Name, Address) is the Entity Type, and PERSON( 28, Anand, Hyderabad) is the entity instance, i.e., the PERSON value at a particular instance.

17. Generalization is ………… process.

(A) top-down

(B) bottom-up

(C) both (A) & (B)

(D) None of these

Answer: B

Explanation: We can define generalization as extracting the common characteristics from two or more classes and combining them into a generalized superclass. A generalization is a Bottom-Up approach.

18. Match the following:

Set-I

I. 2 NF

II. 3 NF

III. 4 NF

IV. 5 NF

Set-II

(a) transitive dependencies eliminated

(b) multivalued attribute removed

(c) contain no partial functional dependencies

(d) contains no join dependency

Codes :

   I II III IV

(A) (a) (c) (b) (d)

(B) (d) (a) (b) (c)

(C) (c) (d) (a) (b)

(D) (d) (b) (a) (c)

Answer: B

Explanation: 

2NF => Contain no partial functional dependencies

3NF => Transitive dependencies eliminated

4NF => Multivalued attribute removed

5NF => Contains no join dependency

19. Which data management language component allowed the DBA to define the schema components?

Answer: C

Explanation: The database task Group(DBTG) specified three separate data management language components to produce the required standardization.

1. Schema DDL: Schema DDL enabled the DBA to define the schema components. 

2. Subschema DDL: It lets the application programs define the database components that the program will use.

3. DML: It helps the manipulation of the database contents.

20. The PROJECT Command will create a new table that has

(A) more fields than the original table

(B) more rows than the original table

(C) both (A) & (B)

(D) none of these

Answer: D

Explanation: We use the Project command to select a relationship column based on the condition given in the query. 

Option(A) is wrong because the maximum number of columns the Project command can select equals the total number of columns in a given relation. 

Option(B) is wrong because the project command is related to the columns of a relation. It is not related to the selection of rows in the table. The result of the Project command contains the same number of rows as that of the given relation.

21.

Answer: D

Explanation:

 

Option A: According to constraint, 

Push(A) then Pop(A)

Push(B) then Pop(B)

Push(C) then Pop(C)

Then the possible pop sequence is ABC. So, it is TRUE.

Option B: According to given constraint, Push(A),Push(B) and Push(C) then Pop(C), Pop(B) and Pop(A). The possible Pop sequence is CBA. So, it is TRUE.

Option C: According to given constraint, Push(A) and Push(B) then Pop(B) and Pop(A) then push(C) and Pop(C). The possible Pop sequence is BAC. So, it is TRUE.

Option D: This is not possible.

22. What is the most suitable data structure to implement a priority queue?

Answer: A

Explanation: The priority queue is an ADT(abstract data type) as a regular queue or stack data structure, but each element has a "priority". 

• An element with higher priority is served before an element with low priority in a priority queue.
• In some cases, if two elements have the same priority, they are served according to the order we enqueued them. In contrast, the ordering of elements with the same priority is undefined in other implementations.
• While priority queues are often implemented with heaps, they are conceptually different from heaps. Priority queues are an abstract concept like a "list" or a "map".
• Just as we can implement a list with a linked list or an array, we can implement a priority queue with a heap or other methods such as an unordered array.

 

23. How far are the two most distant nodes in a complete binary tree of n nodes? Assume that each edge in the path counts as!

Answer: B

Explanation: According to the binary two most distinct nodes are in 

level-1: 1 and 2 

level-2: 3 and 6. 

(Note: Assume that root starts from level-o]

The height of the binary tree is O(log2n). As per the given constraint, we have to calculate individually of left farthest node and right farthest node height =log2n*log2n =2*log n or (log,n)

24. A chained hash table has an array size of 100. What is the maximum number of entries placed in the table?

(A) 100

(B) 200

(C) 10000

(D) There is no upper limit

Answer: D

Explanation: Here are two things we have to remember 

1. They were given a chained hash. It is like a linked list.

2. We can place the Maximum number of entries in the table. In chained hash, we add a new element when collisions happen.

25. In a B tree of order 5, the following keys are inserted as follows:

How many elements are there in the root of the tree?

Answer: B

Explanation: Since the order of the B-tree is 5. 

=>Then maximum no. of the key that can be present in a node = 5 - 1 = 4 keys

=> Minimum no. keys that can be present in a node = [52]-1=2 keys

=> Now 7,8,1, 4 are inserted in a node