## UGC NET CS 2011 Dec-Paper-2

Question 1 |

Which of the following data structure is Non-linear type ?

Strings | |

Lists | |

Stacks | |

None of the above |

Question 1 Explanation:

A data structure is said to be linear if its elements form a sequence or a linear list.

Examples:

1. Array

2. Linked List

3. Stacks

4. Queues

Examples:

1. Array

2. Linked List

3. Stacks

4. Queues

Question 2 |

The total number of comparisons in a bubble sort is

0(log n) | |

0(n log n) | |

0(n) | |

None of the above |

Question 2 Explanation:

The total number of comparisons in a bubble sort is O(n

^{2})Question 3 |

Which of the following is a bad example of recursion ?

Factorial | |

Fibonacci numbers | |

Tower of Hanoi | |

Tree traversal |

Question 3 Explanation:

→ Fibonacci Series using recursion using condition is

Condition: fibonacci(n-1) + fibonacci(n-2)

Recurrence relation is: T(n)=2T(n-1)+C

Time Complexity: O(2

→ Factorial number using recursion is

Condition: fact(n-1)*n

Recurrence relation is: T(n)=T(n+1)+1

Time Complexity: O(n)

→ Tower of Hanoi using recursion is

Step-1: Hanoi(disk - 1, source, aux, dest)

Step-2: move disk from source to dest

Step-3: Hanoi(disk - 1, aux, dest, source)

Recurrence relation is: T(n)=2T(n-1)+C

Time Complexity: O(2

→ Tree traversals like Preorder,Postorder and Inorder using recursion only

Note: Recursion is best in the case of Tower of Hanoi,Factorial number and Tree traversals but it is not give good performance to fibonacci numbers.

Condition: fibonacci(n-1) + fibonacci(n-2)

Recurrence relation is: T(n)=2T(n-1)+C

Time Complexity: O(2

^{n})→ Factorial number using recursion is

Condition: fact(n-1)*n

Recurrence relation is: T(n)=T(n+1)+1

Time Complexity: O(n)

→ Tower of Hanoi using recursion is

Step-1: Hanoi(disk - 1, source, aux, dest)

Step-2: move disk from source to dest

Step-3: Hanoi(disk - 1, aux, dest, source)

Recurrence relation is: T(n)=2T(n-1)+C

Time Complexity: O(2

^{n})→ Tree traversals like Preorder,Postorder and Inorder using recursion only

Note: Recursion is best in the case of Tower of Hanoi,Factorial number and Tree traversals but it is not give good performance to fibonacci numbers.

Question 4 |

Domain and Range of the function Y = -√(-2x + 3) is

x ≥3/2, y ≥ 0 | |

x >3/2, y ≤ 0 | |

x ≥3/2, y ≤ 0 | |

x ≤3/2, y ≤ 0 |

Question 5 |

Maximum number of edges in a n-Node undirected graph without self loop is

n ^{2} | |

n(n-1) | |

n(n+1) | |

n(n-1)/2 |

Question 5 Explanation:

The set of vertices has size n, the number of such subsets is given by the binomial coefficient C(n,2)⋅C(n,2) = n(n-1)/2

Question 6 |

A hash table has space for 75 records, then the probability of collision before the table is 6% full.

25 | |

20 | |

35 | |

30 | |

None of the above |

Question 6 Explanation:

Given data,

-- Hash table has space =75 slots.

-- For 6% filling it must take =6 slots.

-- Probability of no collision for first 6 entries=?

Step-1: According to given data,

= (

-- Hash table has space =75 slots.

-- For 6% filling it must take =6 slots.

-- Probability of no collision for first 6 entries=?

Step-1: According to given data,

= (

^{75}P_{6) / (756) = 0.814586387 Step-2: We have to find at least one collision occurs in 6 entries =1-Probability of no collision for first 6 entries = 1-0.814586387 = 0.185413613 Note: Given options are wrong. Given option-B is correct answer according to original key. }Question 7 |

BCC in the internet refers to

Black carbon copy | |

Blind carbon copy | |

Blank carbon copy | |

Beautiful carbon copy |

Question 7 Explanation:

→ Blind carbon copy(BCC) is a useful way to let others see an email you sent without the main recipient knowing. It is faster than sending the original message and then forwarding the sent message to the other recipients. It is also good netiquette to use Bcc when copying a message to many people.

Question 8 |

Hub is a term used with

A Star Networks | |

A Ring Networks | |

A Router | |

A Bridge |

Question 8 Explanation:

→ Hub is a term used with a star networks. When compare to switch, it is not an intelligent device.

Question 9 |

The amount of uncertainty in a system of symbol is called

Bandwidth | |

Entropy | |

Loss | |

Quantum |

Question 9 Explanation:

→ The amount of uncertainty in a system of symbol is called entropy.
→ Generally we can call entropy is disorder or uncertainty.

Question 10 |

Which of the following network access standard disassembler is used for connection station to a packet switched network ?

X.3 | |

X.21 | |

X.25 | |

X.75 |

Question 10 Explanation:

An X.25 WAN consists of packet-switching exchange (PSE) nodes as the networking hardware, and leased lines, plain old telephone service connections, or ISDN connections as physical links.

Question 11 |

A station in a network in a network forward incoming packets by placing them on its shortest output queue. What routing algorithm is being used ?

Hot potato routing | |

Flooding | |

Static routing | |

Delta routing |

Question 11 Explanation:

→ Hot-potato routing is the practice of passing traffic off to another autonomous system as quickly as possible, thus using their network for wide-area transit.
→ Cold-potato routing is the opposite, where the originating autonomous system holds onto the packet until it is as near to the destination as possible.

Question 12 |

Start and stop bits are used in serial communications for

Error detection
| |

Error correction | |

Synchronization | |

Slowing down the communication |

Question 12 Explanation:

Start and stop bits are used in serial communications for Synchronization.