UGC NET CS 2012 June-Paper2

Question 1
The postfix expression AB + CD – * can be evaluated using a
A
stack
B
tree
C
queue
D
linked list
       Data-Structures       Queues-and-Stacks
Question 1 Explanation: 

Question 2
The post order traversal of a binary tree is DEBFCA. Find out the preorder traversal.
A
ABFCDE
B
ADBFEC
C
ABDECF
D
None of the above
       Data-Structures       Binary-Trees
Question 2 Explanation: 
Post order traversal tree is look like

Postorder: DEBFCA
Inorder: DBEAFC
Preorder: ABDECF
Question 3
The branch logic that provides making capabilities in the control unit is known as
A
Controlled transfer
B
Conditional transfer
C
Unconditional transfer
D
None of the above
       Computer-Organization       Pipelining
Question 3 Explanation: 
The branch logic that provides making capabilities in the control unit is known as controlled transfer.
Question 4
The number of colours required to properly colour the vertices of every planar graph is
A
2
B
3
C
4
D
5
       Engineering-Mathematics       Graph-Theory
Question 4 Explanation: 
→ The 4-colour theorem of the planar graph describes that any planar can at most be colored with 4 colors.
→ The sufficient number of colors in worst case is 4 colors for any planar graph.
Question 5
Networks that use different technologies can be connected by using
A
Packets
B
Switches
C
Bridges
D
Routers
       Computer-Networks       Routing
Question 5 Explanation: 
Switch is a multiport network bridge that uses hardware addresses to process and forward data at the data link layer (layer 2) of the OSI model. Some switches can also process data at the network layer (layer 3) by additionally incorporating routing functionality. Such switches are commonly known as layer-3 switches or multilayer switches.
Hub is basically a multiport repeater. A hub works at the physical layer (layer 1) of the OSI model. A repeater hub also participates in collision detection, forwarding a jam signal to all ports if it detects a collision.
Bridge operates at data link layer. A bridge is a repeater, with add on functionality of filtering content by reading the MAC addresses of source and destination. It is also used for interconnecting two LANs working on the same protocol. It has a single input and single output port, thus making it a 2 port device.
Router is a device like a switch that routes data packets based on their IP addresses. Router is mainly a Network Layer device. Routers normally connect LANs and WANs together and have a dynamically updating routing table based on which they make decisions on routing the data packets. Router divide broadcast domains of hosts connected through it.
Question 6
Both hosts and routers are TCP/IP protocol software. However, routers do not use protocol from all layers. The layer for which protocol software is not needed by a router is
A
Layer – 5 (Application)
B
Layer – 1 (Physical)
C
Layer – 3 (Internet)
D
Layer – 2 (Network Interface)
       Computer-Networks       TCP/IP-Layers
Question 6 Explanation: 
Router works on three layers which are physical layer, data link layer and network layer. It do not works on application layer. So the answer is option(A).
Router can connect two different networks like ethernet and token ring because it have two physical layer, two data link layer and one network layer to change the frame format according to the respective network

Router can't connect two networks which are using different protocols like one is using TCP/IP and other one is using ATM. For connecting such networks GATEWAYS are used because the works on application layer.
Question 7
In multiuser database if two users wish to update the same record at the same time, they are prevented from doing so by
A
Jamming
B
Password
C
Documentation
D
Record lock
       Database-Management-System       Databases
Question 7 Explanation: 
→ In multiuser database if two users wish to update the same record at the same time, they are prevented from doing so by record lock.
→ Record locking is the technique of preventing simultaneous access to data in a database, to prevent inconsistent results.
→ A simple way to prevent this is to lock the file whenever a record is being modified by any user, so that no other user can save data. This prevents records from being overwritten incorrectly, but allows only one record to be processed at a time, locking out other users who need to edit records at the same time.
Question 8
A binary search tree is a binary tree :
A
All items in the left subtree are less than root
B
All items in the right subtree are greater than or equal to the root
C
Each subtree is itself a binary search tree
D
All of the above
       Data-Structures       Binary-Trees
Question 8 Explanation: 
Binary search tree properties: 1. All items in the left subtree are less than root
2. All items in the right subtree are greater than or equal to the root
3. Each subtree is itself a binary search tree
Question 9
What deletes the entire file except the file structure ?
A
ERASE
B
DELETE
C
ZAP
D
PACK
Question 9 Explanation: 
→ PACK statement removes all records marked for deletion permanently.
→ DELETE statement is used to delete existing records in a table.
→ ZAP deletes the entire file except the file structure.
Question 10
Which command is the fastest among the following ?
A
COPY TO
B
COPY STRUCTURE TO
C
COPY FILE
D
COPY TO MFILE-DAT DELIMITED
Question 10 Explanation: 
COPY STRUCTURE TO → It copying the structure rather than file. So, it is fastest among all.
Question 11
B+ tree are preferred to binary tree in Database because
A
Disk capacity are greater than memory capacities
B
Disk access is much slower than memory access
C
Disk data transfer rates are much less than memory data transfer rate
D
Disks are more reliable than memory
       Database-Management-System       B-and-B+-Trees
Question 11 Explanation: 
In B+ tree, each node can store multiple keys because of which number of disk access is less. While in binary tree each node can store only one key value so the number of disk access is greater than B+ tree. Since the disc access time is greater so it is better to have less number of disc accesses. So in that case B+ tree is preferred over binary tree.
Question 12
A Transaction Manager is which of the following ?
A
Maintains a log of transactions
B
Maintains before and after database images
C
Maintains appropriate concurrency control
D
All of the above
       Database-Management-System       Transactions
Question 12 Explanation: 
A transaction manager is one who is responsible for the ACID properties of a transaction.
→ He maintains the log of all transactions and ensures that only each transaction should be either performed completely or not performed at all.
→ Transaction manager ensure consistency preservation by maintaining the before and after database images of a transaction.
→ Multiple transactions can be executed simultaneously but it is the responsibility of transaction manager that the execution of a transaction should not be interfered with by any other transactions executing concurrently. So for that it maintains a appropriate concurrency control.
→ Transaction manager is also responsible for the durability of a transaction that is the changes applied to the database by a committed transaction must persist in the database. These changes must not be lost because of any failure.
Question 13
Leaves of which of the following trees are at the same level ?
A
Binary tree
B
B-tree
C
AVL-tree
D
Expression tree
       Database-Management-System       B-and-B+-Trees
Question 13 Explanation: 
Binary Tree: A binary tree is a tree in which every node is having at most two children. The nodes with zero child are named as leaf nodes and the nodes having 1 or 2 children are termed as parent node.
In a binary tree all leaf nodes may or may not present at same levels.
A binary tree is not necessarily a balanced tree also. It could be a unbalanced tree.

B-tree: A B-tree is a almost complete binary tree in which each node can contains multiple key values and can have multiple children. A tree is complete binary tree if the level before the last level of tree is completely filled and the leaf nodes in such tree are present at the same level only. In below diagram B,C,D are the leaf nodes.

AVL tree: AVL tree is a balanced binary search tree. In this each node can have at most two children and the height of each node can be -1,0,1. A AVL tree is a balanced binary search tree but it is not necessary that each node of this tree are present at same level.

Expression tree: is a specific kind of a binary tree used to represent expressions. These trees can represent expressions that contain both unary and binary operators. In below diagram a,b,c are leaf nodes and the are not present at same level.

Question 14
Which of the following TCP/IP Internet protocol is diskless machine uses to obtain its IP address from a server ?
A
RAP
B
RIP
C
ARP
D
X.25
       Computer-Networks       TCP/IP-Layers
Question 14 Explanation: 
Address resolution protocol(ARP): Protocol is diskless machine uses to obtain its IP address from a server.
Internet Route Access Protocol(RAP): An open distance vector routing protocol for use at all levels of the internet, from isolated LANs to the major routers of an international commercial network provider.
Routing Information Protocol(RAP): An existing protocol for exchanging routing information among gateways and other hosts.
X.25 uses Packet-switching exchange, Data circuit-terminating equipment and Data terminal equipment .
Question 15
Decryption and encryption of data are the responsibility of which of the following layer ?
A
Physical layer
B
Data Link layer
C
Presentation layer
D
Session layer
       Computer-Networks       OSI-TCP-layers
Question 15 Explanation: 
→ The presentation layer handles translation, encryption, authentication and compression.
→ The presentation layer is layer 6 and serves as the data translator for the network.
Question 16
In which circuit switching, delivery of data is delayed because data must be stored and retrieved from RAM ?
A
Space division
B
Time division
C
Virtual
D
Packet
       Computer-Networks       Switching
Question 16 Explanation: 
Time division multiplexing(TDM) delivery of data is delayed because data must be stored and retrieved from RAM.
Question 17
In which Routing Method do all the routers have a common database ?
A
Distance vector
B
Link state
C
Link vector
D
Dijkstra method
       Computer-Networks       Routing
Question 17 Explanation: 
→ Link State Routing(LSR) algorithm after construction of link state packets, new routes are computed using Dijkstra’s algorithm.
→ Each node independently runs an algorithm over the map to determine the shortest path from itself to every other node in the network; generally some variant of Dijkstra's algorithm is used.
→ This is based around a link cost across each path which includes available bandwidth among other things.
→ Link State Routing Method do all the routers have a common database
Question 18
Page Shift Keying (PSK) Method is used to modulate digital signal at 9600 bps using 16 level. Find the line signals and speed (i.e. modulation rate).
A
2400 bauds
B
1200 bauds
C
4800 bauds
D
9600 bauds
Question 18 Explanation: 
Page Shift Keying (PSK) Method uses power of 2 number of bits.
2 level→ 21 → 1 bit
4 level → 22 → 2 bits
8 level → 23 → 3 bits
16 level → 24 → 4 bits
32 level → 25 → 5 bits
Given data,
-- Digital Signal=9600bps
-- 16 levels
-- Baud rate=?
Step-1: Baud rate= Total digital signal / level bits
= 1600 / 4
= 2400 bauds
Question 19
The station to hub distance in which it is 2000 metres.
A
100 Base-Tx
B
100 Base-Fx
C
100 Base-T4
D
100 Base-T1
       Computer-Networks       Hardware-and-various-devices-in-networking
Question 19 Explanation: 

Question 20
Main aim of software engineering is to produce
A
program
B
software
C
within budget
D
software within budget in the given schedule
       Software-Engineering       Software-requirements
Question 20 Explanation: 
Main aim of software engineering is to produce software within budget in the given schedule.
Question 21
Key process areas of CMM level 4 are also classified by a process which is
A
CMM level 2
B
CMM level 3
C
CMM level 5
D
All of the above
       Software-Engineering       Software-Development
Question 21 Explanation: 
CMM stands for Capability Maturity Model is a process model which specifies the process improvement approach in software development.
CMM levels:
1. Initial
2. Repeatable
3. Defined
4. Managed
5. Optimizing
Level-4 (Managed): the process is quantitatively managed in accordance with agreed-upon metrics. It also classified by a process which is in level-5.
Level-5(Optimizing): Process management includes deliberate process optimization (or) improvement.
Question 22
Validation means
A
are we building the product right
B
are we building the right product
C
verification of fields
D
None of the above
       Software-Engineering       Software-Development
Question 22 Explanation: 
Verification and validation are not the same things, although they are often confused. Boehm succinctly expressed the difference as
→ Verification: Are we building the product right?
→ Validation: Are we building the right product?
Question 23
If a process is under statistical control, then it is
A
Maintainable
B
Measurable
C
Predictable
D
Verifiable
Question 23 Explanation: 
→ If a process is under statistical control, then it is predictable.
→ Statistical process control(SPC) helps to ensure that the process operates efficiently, producing more specification conforming products with less waste (rework or scrap).
Question 24
In a function oriented design, we
A
minimize cohesion and maximize coupling
B
maximize cohesion and minimize coupling
C
maximize cohesion and maximize coupling
D
minimize cohesion and minimize coupling
       Software-Engineering       Coupling-and-Cohesion
Question 24 Explanation: 
→ Cohesion is a measure of internal strength within a module, whereas coupling is a measure of inter dependency among the modules.
→ In a functional oriented design/modular software design there should be high cohesion and low coupling.
→ It requires High Fan-In and Low fan-out.
Question 25
Which of the following metric does not depend on the programming language used ?
A
Line of code
B
Function count
C
Member of token
D
All of the above
       Programming       Properties
Question 25 Explanation: 
Function count does not depend on the programming language used. It only counts number of functional entries in the function.
Lines of code (LOC) is a software metric used to measure the size of a computer program by counting the number of lines in the text of the program's source code.
Question 26
A B+ tree index is to be built on the name attribute of the relation STUDENT. Assume that all students names are of length 8 bytes, disk block are of size 512 bytes and index pointers are of size 4 bytes. Given this scenario what would be the best choice of the degree (i.e. the number of pointers per node) of the B+ tree ?
A
16
B
42
C
43
D
44
       Database-Management-System       B-and-B+-Trees
Question 26 Explanation: 
Let P be the degree of the nodes.
Then,
8(P-1) + 4P ≤ 512
12P - 8 ≤ 512
12P ≤ 520
P ≤ 43.33
P = 43
Question 27
The Inorder traversal of the tree will yield a sorted listing of elements of tree in
A
Binary tree
B
Binary search tree
C
Heaps
D
None of the above
       Database-Management-System       B-and-B+-Trees
Question 27 Explanation: 
Inorder traversal technique in binary search tree will always produce ascending order.
Question 28
Mobile IP provides two basic functions.
A
Route discovery and registration
B
Agent discovery and registration
C
IP binding and registration
D
None of the above
       Computer-Networks       IP-Adress
Question 28 Explanation: 
→ Mobile IP provides two basic functions are IP binding and registration.
→ A binding is the association of the home address with a care-of address.
Question 29
Preemptive scheduling is the strategy of temporarily suspending a gunning process
A
Before the CPU time slice expires
B
To allow starving processes to run
C
When it requests I/O
D
To avoid collision
       Operating-Systems       Process-Scheduling
Question 29 Explanation: 
→ Preemptive scheduling is the strategy of temporarily suspending a gunning process before the CPU time slice expires.
→ Preemptive scheduling means the processes is always interrupted by higher priorities.
Question 30
In round robin CPU scheduling as time quantum is increased the average turnaround time
A
increases
B
decreases
C
remains constant
D
varies irregularly
       Operating-Systems       CPU-Scheduling
Question 31
Resources are allocated to the process on non-sharable basis is
A
mutual exclusion
B
hold and wait
C
no pre-emption
D
circular wait
       Operating-Systems       Deadlock
Question 31 Explanation: 
Resources are allocated to the process on non-sharable basis is mutual exclusion.
Question 32
Cached and interleaved memories are ways of speeding up memory access between CPU’s and slower RAM. Which memory models are best suited (i.e. improves the performance most) for which programs ?
(i) Cached memory is best suited for small loops.
(ii) Interleaved memory is best suited for small loops
(iii) Interleaved memory is best suited for large sequential code.
(iv) Cached memory is best suited for large sequential code.
A
(i) and (ii) are true.
B
(i) and (iii) are true.
C
(iv) and (ii) are true.
D
(iv) and (iii) are true.
       Computer-Organization       Cache
Question 32 Explanation: 
→ Interleaved memory is a design made to compensate for the relatively slow speed of dynamic random-access memory (DRAM) or core memory, by spreading memory addresses evenly across memory banks.
That way, contiguous memory reads and writes are using each memory bank in turn, resulting in higher memory throughputs due to reduced waiting for memory banks to become ready for desired operations.
→ A CPU cache is a hardware cache used by the central processing unit (CPU) of a computer to reduce the average cost (time or energy) to access data from the main memory.
→ A cache is a smaller, faster memory, closer to a processor core, which stores copies of the data from frequently used main memory locations.
→ Loops consist of frequently used variables.
Question 33
Consider the following page trace :
4,3, 2, 1, 4, 3, 5, 4, 3, 2, 1, 5
Percentage of page fault that would occur if FIFO page replacement algorithm is used with number of frames for the JOB m = 4 will be
A
8
B
9
C
10
D
12
       Operating-Systems       Page-Replacement-algorithm
Question 33 Explanation: 

Total 10 page faults will happen.
Question 34
Checksum used along with each packet computes the sum of the data, where data is treated as a sequence of
A
Integer
B
Character
C
Real numbers
D
Bits
       Computer-Networks       Checksum
Question 34 Explanation: 
Checksum used along with each packet computes the sum of the data, where data is treated as a sequence of bits.
Question 35
If an integer needs two bytes of storage, then the maximum value of a signed integer is
A
216 – 1
B
215 – 1
C
216
D
215
       Digital-Logic-Design       Number-Systems
Question 35 Explanation: 
= If an integer needs two bytes of storage, then the maximum value of a signed integer is 2n-1 -1
= 215 -1
Question 36
Which of the following logic families is well suited for high-speed operations ?
A
TTL
B
ECL
C
MOS
D
CMOS
Question 36 Explanation: 
Emitter Coupled Logic (ECL)
The storage time is eliminated as the transistors are used in difference amplifier mode and are never driven into saturation.
1. Fastest among all logic families
2. Lowest propagation delay.
Complementary metal oxide semiconductor(CMOS) The power dissipation is usually 10nW per gate depending upon the power supply voltage, output load etc.
1. Lowest power dissipation
2. Excellent noise immunity
3. High packing density
4. Wide range of supply voltage
5. Highest fan out among all logic families
Question 37
Interrupts which are initiated by an instruction are
A
Internal
B
External
C
Hardware
D
Software
       Computer-Organization       Interrupt-Service-Routing
Question 37 Explanation: 
→ An interrupt is a signal to the processor emitted by hardware or software indicating an event that needs immediate attention.
→ A software interrupt is caused either by an exceptional condition in the processor itself, or a special instruction in the instruction set which causes an interrupt when it is executed.
→ The former is often called a trap or exception and is used for errors or events occurring during program execution that are exceptional enough that they cannot be handled within the program itself.
→ Hardware interrupts are used by devices to communicate that they require attention from the operating system.
Question 38
printf(“%c”, 100);
A
prints 100
B
prints ASCII equivalent of 100
C
prints garbage
D
none of the above
       Programming       ASCII
Question 38 Explanation: 
printf(“%c”, 100); → It prints ASCII equivalent of 100.
→ It prints character ‘b’.
Question 39
For the transmission of the signal, Bluetooth wireless technology uses
A
time division multiplexing
B
frequency division multiplexing
C
time division duplex
D
frequency division duplex
       Computer-Networks       Wi-Fi
Question 39 Explanation: 
→ Bluetooth wireless technology uses time division duplex.
→ Bluetooth uses less power and costs less to implement than Wi-Fi. Its lower power also makes it far less prone to suffering from or causing interference with other wireless devices in the same 2.4GHz radio band.
→ Bluetooth devices also shift radio frequencies often while paired, which prevents easy invasion.
Question 40
Consider the following statements :
(I). Recursive languages are closed under complementation.
(II). Recursively enumerable languages are closed under union.
(III). Recursively enumerable languages are closed under complementation.
Which of the above statements are true ?
A
I only
B
I and II
C
I and III
D
II and III
       Theory-of-Computation       Closure-Property
Question 40 Explanation: 
→ Recursive closed under union,intersection,complementation,etc.., except Homomorphism and substitution.
→ Recursively enumerable languages are closed under union,intersection,etc.., except set difference and complementation.
Question 41
What is the routing algorithm used by RIP and IGRP ?
A
OSPF
B
Link-state
C
Dynamic
D
Dijkstra vector
E
None of the above
       Computer-Networks       Routing
Question 41 Explanation: 
→ The distance vector algorithm was the original ARPANET routing algorithm and was implemented more widely in local area networks with the Routing Information Protocol (RIP).
→ Interior Gateway Routing Protocol (IGRP) is an advanced distance-vector routing protocol that is used on a computer network for automating routing decisions and configuration.
Note: Dijkstra’s algorithm used for List State Routing(LSR). They given Dijkstra vector instead of distance vector. Excluded for evaluation.
Question 42
Identify the incorrect statement :
A
The overall strategy drives the E-Commerce data warehousing strategy.
B
Data warehousing in an E-Commerce environment should be done in a classical manner.
C
E-Commerce opens up an entirely new world of web server.
D
E-Commerce security threats can be grouped into three major categories.
Question 42 Explanation: 
TRUE: The overall strategy drives the E-Commerce data warehousing strategy.
TRUE: Data warehousing in an E-Commerce environment should be done in a classical manner.
TRUE: E-Commerce opens up an entirely new world of web server.
FALSE: E-Commerce security threats can be grouped into more than three major categories.
Question 43
Reliability of software is directly dependent on
A
quality of the design
B
number of errors present
C
software engineers experience
D
user requirement
       Software-Engineering       Software-Reliabiliy
Question 43 Explanation: 
→ Reliability of software is directly dependent on number of errors present.
→ Software Reliability is the probability of failure-free software operation for a specified period of time in a specified environment.
→ The program does not fail for a specified time in a given environment
Question 44
______ is not an E-Commerce application.
A
House banking
B
Buying stocks
C
Conducting an auction
D
Evaluating an employee
Question 44 Explanation: 
E-Commerce application: 1. Online retailing 2. Electric markets 3. Online auctions. 4. House banking 5. Buying stocks
Question 45
______ is a satellite based tracking system that enables the determination of person’s position.
A
Bluetooth
B
WAP
C
Short Message Service
D
Global Positioning System
Question 45 Explanation: 
Global Positioning System(GPS) is a satellite based tracking system that enables the determination of person’s position.
Question 46
A complete microcomputer system consists of
A
Microprocessor
B
Memory
C
Peripheral equipment
D
All of the above
       Computer-Organization       Microprocessor
Question 46 Explanation: 
A complete microcomputer system consists of Microprocessor,Memory and Peripheral equipment.
Question 47
Where does a computer add and compare data ?
A
Hard disk
B
Floppy disk
C
CPU chip
D
Memory chip
Question 47 Explanation: 
CPU Chip carries out the instructions of a computer program by performing the basic arithmetic, logic, controlling, and input/output (I/O) operations specified by the instructions.
Question 48
Pipelining strategy is called implement
A
instruction execution
B
instruction prefetch
C
instruction decoding
D
instruction manipulation
       Computer-Organization       Pipelining
Question 48 Explanation: 
→ Instruction prefetch is a technique used in central processor units to speed up the execution of a program by reducing wait states.
→ Pipelining strategy is called implement instruction prefetch.
Question 49
Which of the following data structure is linear type ?
A
Strings
B
Lists
C
Queues
D
All of the above
       Data-Structures       Lnear-Data-Structure
Question 49 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
Question 50
To represent hierarchical relationship between elements, which data structure is suitable ?
A
Dequeue
B
Priority
C
Tree
D
All of the above
       Data-Structures       Binary-Trees
Question 50 Explanation: 
Double-Ended Queue is a data structure in which insertion and deletion of data takes place from different ends. The insertion of data takes place from REAR end and deletion of data takes place from FRONT end. It follows FIFO( First In First Out) order for implementation.

Priority Queue is like a regular queue or stack data structure, but here each element has a "priority" associated with it. In a priority queue, an element with high priority is served before an element with low priority.
Tree: A tree is a data structure containing a collection of nodes. Here a node can have any number of children. A node with no child is called as leaf node and a node with 1 or more child is called parent node. Each parent node have a pointer to its children.

There are 50 questions to complete.
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