## Saturday, 4 April 2015

### UGC NET Computer Science Previous Paper II June 2009 - Part 1

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)
2.       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
3.       The Boolean expression x’y’z+yz+xz is equivalent to:
(A) x                   (B) y
(C) z                   (D) x+y+z
4.       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
5.       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
6.       The throughput of pure ALOHA is given by:
(A) S=G (B) S=e2G
(C) S=Ge2G       (D) Ge-2G
7.       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
8.       To employ multi-access in GSM, users are given different:
(A) time slots     (B) bandpass filters
(C) handsets    (D) frequency bands
9.       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%
10.    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

11.    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
12.    The complete graph with four vertices has k edges where k is:
(A) 3                   (B) 4
(C) 5                   (D) 6
13.    The octal equivalent of hexadecimal (A.B)16 is:
(A) 47.21                       (B) 12.74
(C) 12.71                       (D) 17.21
14.    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
15.    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
16.    Which of the following does not represent a valid storage class in ’c’?
(A) automatic    (B) static
(C) union          (D) extern
17.    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
18.    (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
19.    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
20.    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

Part 1   Part 2