UGC NET Computer Science Solved Questions December 2013 Paper 3 - Part 6

51.       Synchronization is achieved by a timing device called a ................. which generates a periodic train of ..................
(A) clock generator, clock pulse
(B) master generator, clock pulse
(C) generator, clock
(D) master clock generator, clock pulse
Answer: A and D
52.       Serial access memories are useful in applications where
(A) Data consists of numbers
(B) Short access time is required.
(C) Each stored word is processed differently.
(D) None of these
Answer: D
data naturally needs to flow in and out in serial form.
53.       What will be the output of the following logic diagram?
(A) x OR y
(B) x AND y
(C) x XOR y
(D) x XNOR y
Answer: C
Output at (1) xy’ and at (2) x’y
Finally at (3) xy’ + x’y , x y
54.       The essential difference between traps and interrupts is
(A) traps are asynchronous and interrupts are synchronous with the program
(B) traps are synchronous and interrupts are asynchronous with the program
(C) traps are synchronous and interrupts are asynchronous with the I/O devices.
(D) None of these.
Answer: B
55.       Consider the following ER diagram:
The minimum number of tables required to represent M, N, P, R1, R2 is
(A) 2
(B) 3
(C) 4
(D) 5
Answer: A
Since R1 is many to one and participation of M is total, M and R1 can be combined to form the table {M1, M2, M3, P1}. N is a week entity set, so it can be combined with P.
56.       Consider the following schemas:
Branch = (Branch-name, Assets, Branch-city)
Customer = (Customer-name, Bank-name, Customer-city)
Borrow = (Branch-name, loan-number, customer account-number)
Deposit = (Branch-name, Account-number, Customer-name, Balance)
Using relational Algebra, the query that finds customers who have balance more than 10,000 is .................
(A) πcustomer-namebalance >10000(Deposit))
(B) σcustomer-namebalance >10000(Deposit))
(C) πcustomer-namebalance >10000(Borrow))
(D) σcustomer-namebalance >10000(Borrow))
Answer: A
57.       Find the false statement:
(A) The relationship construct known as the weak relationship type was defined by Dey, Storey & Barron (1999).
(B) A weak relationship occurs when two relationship types are linked by either Event-Precedent sequence or Condition-Precedent sequence
(C) Conceptual model is not accurate representation of "Universe of interest".
(D) Ternary, Quaternary and Quintary relationships are shown through a series of application scenario's and vignette's
Answer: C
58.       Consider the table
Student(stuid, name, course, marks). Which one of the following two queries is correct to find the highest marks student in course 5?
Q.1.        Select S.stuid
From student S
Where not exists
(select * from student e where e course='5' and e marks ≥ s marks)
Q.2.        Select S.stuid
From student S
Where s.marks > any (select distinct marks from student S where s.couse = 5)
(A) Q.1
(B) Q.2
(C) Both Q.1 and Q.2
(D) Neither Q.1 nor Q.2
Answer: B
59.       Armstrong (1974) proposed systematic approach to derive functional dependencies. Match the following w.r.t. functional dependencies.
List - I   
a. Decomposition rule           
b. Union rule   
c. Composition rule
d. Pseudo transitivity rule
List - II
i. If X→Y and Z→W then {X, Z}→{Y, W}
ii. If X→Y and {Y, W}→Z then {X, W}→Z
iii. If X→Y and X→Z then X→{Y, Z}
iv. If X→{Y, Z} then X→Y and X→Z
      a   b   c   d
(A) iii   ii   iv   i
(B) i    iii   iv  ii
(C) ii   i    iii   iv
(D) iv  iii   i   ii
Answer: D
60.    Match the following:
List – I
a. Secondary Index
b. Non-procedural Query
c. Closure of set of Attributes           
d. Natural JOIN           
List - II
i. Functional Dependency
ii. B-tree
iii. Relational Algebraic Operation
iv. Domain Calculus
     a   b  c   d
(A) i   ii   iv  iii 
(B) ii   i   iv  iii
(C) i   iii  iv  ii
(D) ii  iv  i    iii
Answer: D

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