# UGC NET Computer Science Solved Paper II- JUNE 2009

1. If x and y are independent Gaussian random variables with average value 0 and with same variance, their joint probability density function is given by:

(A) p(x,y)=p(x).p(y)       (B) p(x,y)=p(x)+p(y)

(C) p(x,y)=p(x+y)          (D) p(x,y)=p(x).p(y)+p(x)

Answer: marks to all because question is not correct

1. In order that a code is ‘t’ error correcting, the minimum Hamming distance should be:

(A) t                    (B) 2t-1

(C) 2t                  (D) 2t+1

1. The Boolean expression x’y’z+yz+xz is equivalent to:

(A) x                   (B) y

(C) z                   (D) x+y+z

1. The characteristic equation of a JK flip flop is:

(A) Qn+1=J.Qn+K.Qn                  (B) Qn+1=J.Q’n+K’.Qn

(C) Qn+1=QnJ.K                        (D) Qn+1=(J+K)Qn

1. In order to implement a n variable switching function, a MUX must have:

(A) 2n inputs     (B) 2n+1 inputs

(C) 2n-1 inputs   (D) 2n-1 inputs

1. The throughput of pure ALOHA is given by:

(A) S=G (B) S=e2G

(C) S=Ge2G       (D) Ge-2G

1. The Fiber Distributed Data Interface uses:

(A) single mode fibers and LEDs

(B) multimode fibers and LEDs

(C) single mode fibers and ILDs

(D) multimode fibers and ILDs

1. To employ multi-access in GSM, users are given different:

(A) time slots     (B) bandpass filters

(C) handsets    (D) frequency bands

1. With a four programs in memory and with 80% average I/O wait, the CPU utilization is?

(A) 60% (B) 70%

(C) 90% (D) 100%

Explanation

The CPU utilization can be modeled by the formula:-
CPU utilization = 1 – p^n
Here n is number of process and P is the time waiting for I/O.
In your question n=4 and p =.80
so Utilization is 1-.8^4 which is .6(i.e. 60%)

1. Assume N segments in memory and a page size of P bytes. The wastage on account of internal fragmentation is:

(A) NP/2 bytes  (B) P/2 bytes

(C) N/2 bytes    (D) NP bytes

1. Assertion(A): Bit maps are not often used in memory management.

Reason(R): Searching a bitmap for a run of given length is a slow operation.

(A) Both (A) and (R) are true and (R) is correct explanation for (A)

(B) Both(A) and (R) are true but (R) is not correct explanation for (A)

(C) (A) is true (R) is false

(D) (A) is false (R) is true

1. The complete graph with four vertices has k edges where k is:

(A) 3                   (B) 4

(C) 5                   (D) 6

Explanation

1. The octal equivalent of hexadecimal (A.B)16 is:

(A) 47.21                       (B) 12.74

(C) 12.71                       (D) 17.21

Explanation

1. A reduced state table has 18 rows. The minimum number of flip flops needed to implement the sequential machine is:

(A) 18                 (B) 9

(C) 5                   (D) 4

Explanation

apply 2^n >=18

so option c is correct where n=5

1. What is the value of ‘b’ after the execution of the following code statements:

C=10;

B=++c + ++c;

(A) 20                 (B) 22

(C) 23                 (D) None

B= 12 + 12 = 24

1. Which of the following does not represent a valid storage class in ’c’?

(A) automatic    (B) static

(C) union          (D) extern

Explanation:

1. The friend functions are used in situations where:

(B) Dynamic binding is required

(C) Exchange of data between classes to take place

(D) None of the above

1. (i) DML includes a query language based on both relation algebra and tuple calculus

(ii) DML includes a query language based on tuple calculus

(iii) DML includes a query language based on relational algebra

(iv) DML includes a query language based on none of the relational algebra and tuple calculus

Which one is correct?

(A) (i) only         (B) (ii) only

(C) (iii) only       (D) (iv) only

1. Suppose it takes 100 ns to access a page table and 20 ns to access associative memory with a 90% hit rate, the average access time equals:

(A) 20 ns                       (B) 28 ns

(C) 90 ns                       (D) 100 ns

1. There exists a construct which returns a value ‘true’ if the argument subquery is:

(A) empty           (B) non-empty

(C) in error        (D) none of the above

1. Which construct in SQL is used to test whether a subquery has any tuples in its result?

(A) UNIQUE                  (B) EXISTS

(C) GROUP BY            (D) EXCEPT

1. ORACLE supports:

(A) inner join and outer join only

(B) outer join and semi join only

(C) inner join, outer join , semi join only

(D) inner join, outer join, semi join and anti join

1. Which two of the following are equivalent for an undirected graph  G?

(i) G is a tree

(ii) There is at least one path between any two distinct vertices of G

(iii) G contains no cycles and has (n-1) edges

(iv) G has n edges

(A) (i) and (ii)

(B) (i) and (iii)

(C) (i) and (iv)

(D) (ii) and (iii)

1. In a B tree of order m with p nodes the average number of splits is at most:

1. The prepositional formula given by the tree:

is:

(A) ˄˅x2˅x1¬x1¬x1

(B) (x2˅¬x2)˄(x1˅x2)

(C) (¬x1˅x2)˄(¬x1˅x2)

(D) None

1. Queue is a …………. list.

(A) LIFO             (B) LILO

(C) FILO               (D) FIFO

Explanation:

1. In a full binary tree of height k, there are …………….. internal nodes.

(A) 2k-1              (B) 2k-1

(C) 2k                  (D) 2k+1

1. A binary tree is said to have heap property if the elements along any path:

(A) from leaf to root are non-increasing

(B) from leaf to root are non-decreasing

(C) from root to leaf are non-decreasing

(D) from root to leaf are non-increasing

1. X.25 protocol consists of:

(A) Physical and Frame levels

(B) Frame and Packet levels

(C) Physical, Frame and Packet levels

(D) None of the above

1. GSM/CDMA systems:

(A) are limited to very low speed data

(B) require no local loop wires

(C) are predominantly used for voice

(D) all of the above

1. Usually information security in a network is achieved by:

(A) Layering                  (B) Cryptography

(C) Grade of service    (D) None of the above

(A) is similar to interpreter

(B) uses source code as its input

(C) is required to create a load module

(D) none of the above

1. In which addressing mode the operand is given explicitly in the instruction itself?

(A) Absolute mode      (B) Immediate mode

(C) Indirect mode         (D) Index mode

1. A compiler that runs on one machine and produces code for a different machine is called:

(A) Cross compilation             (B) One pass compilation

(C) Two pass compilation      (D) None of the above

1. Any syntactic construct that can be described by a regular expression can also be described by a:

(A) Context sensitive grammar

(B) Non context free grammar

(C) Context free grammar

(D) None of the above

1. Find the odd man out:

(A) tail                (B) cut

(C) wart              (D) sed

1. Which of the following changes permission to deny write permission to group and others?

(A) Chmod go-w filex              (B) Chmod go w filex

(C) Chmod go=w filex             (D) None of the above

1. Variable partition memory management technique with compaction results in:

(A) Reduction of fragmentation

(B) Minimal wastage

(C) Segment sharing

(D) None of the above

1. Capability Maturity Model is meant for:

(A) Product                               (B) Process

(C) Product and Process        (D) None of the above

1. In the light of software engineering software consists of:

(A) Programs                (B) Data

(C) Documentation     (D) All of the above

1. Which one of the following ISO standard is used for software process?

(A) ISO 9000     (B) ISO 9001

(C) ISO 9003    (D) ISO 9000-3

1. Which of the following is used for test data generation?

(A) White box                           (B) Black box

(C) Boundary-value analysis            (D) All of the above

1. Reverse engineering is the process which deals with:

(A) Size measurement            (B) Cost measurement

(C) Design recovery                (D) All of the above

1. The spacing between character pairs is called:

(A) Kerning       (B) x-height

(C) intercap       (D) serif

1. When compared with analog cellular systems, an advantage of digital TDMA cellular system is that:

(A) it is less complicated

(B) it requires less of computer memory

(C) it conserves spectrum bandwidth

(D) it costs less

1. E-commerce includes:

(A) B2C (B) B2B

(C) C2C (D) All of the above

1. A clustering technique that permits a convenient graphical display is:

(A) partition based clustering

(B) probabilistic model based clustering

(C) hierarchical clustering

(D) agglomerative clustering

1. After sending a message, the sender should not be able to, at a later date, deny having sent the message, is referred to as:

(A) Authenticity                        (B) Non-Repudiability

(C) Auditability             (D) Repudiability

1. The device which connects dissimilar LANs of different topologies using different sets of communication protocols so that information can flow from one to another is called:

(A) Router                     (B) Bridge

(C) Gateway                 (D) Switch