Tuesday, 3 January 2017

UGC Net Computer Science Paper II Dec 12,Page 5 (Solve)

UGC Net Computer Science Paper II Dec 12,Page 5 (Solve)
41. Enumeration is a process of
(A) Declaring a set of numbers
(B) Sorting a list of strings
(C) Assigning a legal values possible for a variable
(D) Sequencing a list of operators
Answer C
Explanation : Enumeration is a special datatype which provide an integer number sequence to its member which help to track some common properties with meaning full name instead of number like color names

42. Which of the following mode declaration is used in C++ to open a file for input ?
(A) ios : : app
(B) in : : ios
(C) ios : : file
(D) ios : : in
Answer D
Explanation : ios::in allows input (read operations) from a stream.ios::out allows output (write operations) to a stream.

43. Data Encryption Techniques are particularly used for ______.
(A) protecting data in Data Communication System.
(B) reduce Storage Space Requirement.
(C) enhances Data Integrity.
(D) decreases Data Integrity.
Answer A
Explanation : when we send our data through public network then eavesdropping risk become high So we need some technique which increase security when data is send through public network.

Data encryption translates data into another form, or code, so that only people with access to a secret key (formally called a decryption key) or password can read it. Encrypted data is commonly referred to as ciphertext, while unencrypted data is called plaintext. Currently, encryption is one of the most popular and effective data security methods used by organizations. Two main types of data encryption exist - asymmetric encryption, also known as public-key encryption, and symmet

44. Let L be a set accepted by a non deterministic finite automaton. The number of states in non-deterministic finite automaton is |Q|. The maximum number of states in equivalent finite automaton that accepts L is
(A) |Q|
(B) 2|Q|
(C) 2|Q| – 1
(D) 2|Q|
Answer D
Explanation :In NFA there may be possibility to more than one state transition but in DFA state transition is single direction so about this question if NFA is |Q| then DFA may have 2|Q| state over this type of NFA.

45. What is the result of the following expression ?

(1 & 2) + (3 & 4)

(A) 1
(B) 3
(C) 2
(D) 0
Answer D
Explanation :& is bitmap compare a number at binary level from right to left and operator which return true when all operand is true otherwise false so after evaluate the given expression result become false .
(01 &  10)    +  (011 & 100)

0+0=0

46. Back propagation is a learning technique that adjusts weights in the neural network by propagating weight changes.
(A) Forward from source to sink
(B) Backward from sink to source
(C) Forward from source to hidden nodes
(D) Backward from since to hidden nodes
Answer B

47. Match the following :

a. TTL       1. High fan out
b. ECL      2. Low propagation delay
c. CMOS   3. High power dissipation

Code :
      a    b    c
(A) 3   2    1
(B) 1   2    3
(C) 1   3    2
(D) 3   1    2
Answer A
Explanation : 


a.TTL draws more power => 3
b. ECL has highest speed ; Hence it must have lowest propagation delay =>2
c. CMOS has high fan out =>1

48. ______ is an “umbrella” activity that is applied throughout the software engineering process.

.(A) Debugging
(B) Testing
(C) Designing
(D) Software quality assurance
Answer D
Explanation : 
The umbrella activities in a software development life cycle process include the following:
  • Software Project Management
  • Formal Technical Reviews
  • Software Quality Assurance
  • Software Configuration Management
  • Re-usability Management
  • Risk Management
  • Measurement and Metrics
Document Preparation and Production

49. Identify the operation which is commutative but not associative ?
(A) OR
(B) NOR
(C) EX-OR
(D) NAND

Answer D
Explanation :


1)Every logic gate follows Commutative law.

2)AND,OR,Ex-OR,EX-NOR follows Associative law. NAND,NOR doesn`t follow Associative law.

3)AND ,OR follows Distributive law.Ex-OR,EX-NOR,NAND,NOR doesn`t follow Distributive law.AND operation only distributive on EX-OR operation no other operation is distributive including itself.


50. Given a Relation POSITION (Posting-No, Skill), then query to retrieve all distinct pairs of posting-nos. requiring skill is

 (A) Select p.posting-No, p.posting-No from position p 
         where p.skill = p.skill     and p.posting-No < p.posting-No
(B) Select p1.posting-No, p2.posting-No   from position p1, position p2
       where p1.skill = p2.skill
(C) Select p1.posting-No, p2.posting-No  from position p1, position p2 
       where p1.skill = p2.skill   and p1.posting-No < p2.posting-No
(D) Select p1.posting-No, p2.posting-No   from position p1, position p2
      where p1.skill = p2.skill    and p1.posting-No = p2.posting-No
Answer C