Computer Science Study Materials for Competitive Exams

Sample Questions, Previous Year Solved Papers, Study Materials For Competitive Examinations Like UGC NET, SET And GATE Computer Science.

Saturday, 30 July 2016

11.       Consider the following ORACLE relations:
R(A,B,C) = {<1,2,3>, <1,2,0>, <1,3,1>, <6,2,3>, <1,4,2>, <3,1,4>}
S(B,C,D) = {<2,3,7>, <1,4,5>, <1,2,3>, <2,3,4>, <3,1,4>}
Consider the following two SQL queries SQ1 and SQ2:
SQ1: SELECT R.B, AVG(S.B)
FROM R, S
WHERE R.A = S.C AND S.D < 7
GROUP BY R.B;
SQ2: SELECT DISTINCT S.B, MIN (S.C)
FROM S
GROUP BY S.B
HAVING COUNT (DISTINCT S.D) > 1;
If M is the number of tuples returned by SQ1 and N is the number of tuples returned by SQ2 then
(A) M=4, N=2                (B) M=5, N=3
(C) M=2, N=2                (D) M=3, N=3
Answer: A
12.       Semi-join strategies are techniques for query processing in distributed database system. Which of the following is a semi-join technique?
(A) Only the joining attributes are sent from one site to another and then all of the rows are returned.
(B) All of the attributes are sent from one site to another and then only the required rows are returned.
(C) Only the joining attributes are sent from one site to another and then only the required rows are returned.
(D) All of the attributes are sent from one site to another and then only the required rows are returned.
Answer: C
13.       Consider the Breshenham’s circle generation algorithm for plotting a circle with centre (0,0) and radius ‘r’ units in first quadrant. If the current point is (x1,y1) and decision parameter is pi then what will be the next point (xi+1,yi+1) and updated decision parameter pi+1 for pi ≥ 0
(A) xi+1 = xi + 1               yi+1 = yi            pi+1 = pi + 4xi + 6
(B) xi+1 = xi + 1               yi+1 = yi - 1      pi+1 = pi + 4(xi - yi) + 10
(C) xi+1 = xi                     yi+1 = yi - 1      pi+1 = pi + 4(xi - yi) + 6
(D) xi+1 = xi - 1                yi+1 = yi            pi+1 = pi + 4xi + 10
Answer: B
14.       A point P(5,1) is rotated by 900 about a pivot point (2,2). What is the coordinate of new transformed point P’ ?
(A) (3,5)             (B) (5,3)
(C) (2,4)             (D) (1,5)
Answer: A
15.       Let R be the rectangular window against which the lines are to be clipped using 2D Sutherland-Cohen line clipping algorithm. The rectangular window has lower left-hand corner at (-5,1) and upper right-hand corner at (3,7). Consider the following three lines for clipping with the given end point co-ordinates:
Line AB: A(-6,2) and B(-1,8)
Line CD: C(-1,5) and D(4,8)
Line EF: E(-2,3) and F(1,2)
Which of the following line(s) is/are candidate for clipping?
(A) AB                (B) CD
(C) EF                (D) AB and CD
Answer: D

16.       In perspective projection, if a line segment joining a point which lies in front of the viewer to a point in back of the viewer is projected to a broken line of infinite extent. This is known as ...................
(A) View confusion                 (B) Vanishing point
(C) Topological distortion       (D) Perspective foreshortening
Answer: C
17.       Let us consider that the original point is (x,y) and new transformed point is (x’,y’). Further, Shx and Shy are shearing factors in x and y directions. If we perform the y-direction shear relative to x=xref then the transformed point is given by ............
(A) x’ = x + Shx . (y - yref)                      y’ = y
(B) x’ = x            y’ = y . Shx
(C) x’ = x            y’ = Shy(x - xref) + y
(D) x’ = Shy . y              y’ = y . (x - xref)
Answer: C
18.       Which of the following statement(s) is/are correct with reference to curve generation?
I. Hermite curves are generated using the concepts of interpolation.
II. Bezier curves are generated using the concepts of approximation.
III. The Bezier curves lies entirely within the convex hull of its control points.
IV. The degree of Bezier curve does not depend on the number of control points.
(A) I, II and IV only                   (B) II and III only
(C) I and II only                                    (D) I, II and III only
Answer: D
19.       Given the following statements:
(a) To implement Abstract Data Type, a programming language require a syntactic unit to encapsulate type definition.
(b) To implement ADT, a programming language requires some primitive operations that are built in the language processor.
(c) C++, Ada, Java 5.0, C#2005 provide support for parameterised ADT.
Which one of the following options is correct?
(A) (a), (b) and (c) are false.
(B) (a) and (b) are true; (c) are false.
(C) (a) is true; (b) and (c) are false.
(D) (a), (b) and (c) are true.
Answer: D
20.    Match the following types of variables with the corresponding programming languages:
(a) Static variables                   (i) Local variables in Pascal
(b) Stack dynamic                    (ii) All variables in APL
(c) Explicit heap dynamic       (iii) Fortran 77
(d) Implicit heap dynamic       (iv) All objects in JAVA
Codes:
      (a)   (b)   (c)   (d)
(A) (i)    (iii)  (iv)   (ii)
(B) (iv)  (i)    (iii)   (ii)
(C) (iii)  (i)    (iv)   (ii)
(D) (ii)   (i)    (iii)   (iv)
Answer: C


Wednesday, 27 July 2016

1.       Which of the following is a sequential circuit?
(A) Multiplexer  (B) Decoder
(C) Counter      (D) Full adder
Answer: C
2.       8085 microprocessor has ............. hardware interrupts.
(A) 2       (B) 3
(C) 4       (D) 5
Answer: D
3.       Which of the  following in 8085 microprocessor performs
HL = HL + DE ?
(A) DAD D         (B) DAD H
(C) DAD B         (D) DAD SP
Answer: A
4.       The Register that stores all interrupt requests is:
(A) Interrupt mask register      (B) Interrupt service register
(C) Interrupt request register (D) Status register
Answer: C
5.       The ............... addressing mode is similar to register indirect addressing mode, except that an offset is added to the contents of the register. The offset and register are specified in the instruction.
(A) Base indexed         (B) Base indexed plus displacement
(C) Indexed                   (D) Displacement
Answer: D

6.       In ............. method, the word is written to the block in both the cache and main memory, in parallel.
(A) Write through                     (B) Write back
(C) Write protected                  (D) Direct mapping
Answer: A
7.       Which of the following statements concerning Object-Oriented databases is FALSE?
(A) Objects in an object-oriented database contain not only data but also methods for processing the data.
(B) Object-oriented databases store computational instructions in the same place as the data.
(C) Object-oriented databases are more adapt at handling structures (analytical) data than relational databases.
(D) Object-oriented databases store more types of data than relational databases and access that data faster.
Answer: C
8.       In distributed databases, location transparency allows for database users, programmers and administrators to treat the data as if it is at one location. A SQL query with location transparency needs to specify:
(A) Inheritances           (B) Fragments
(C) Locations                (D) Local formats
Answer: B
9.       Consider the relations R(A,B) and S(B,C) and the following four relational algebra queries over R and S:
I. πA,B(RS)
II. RπB(S)
III. R∩(πA(R) Χ πB(S))
IV. πA,R.B(R Χ S) where R.B refers to the column B in table R.
One can determine that:
(A) I, III and IV are the same query.
(B) II, III and IV are the same query.
(C) I, II and IV are the same query.
(D) I, III and III are the same query.
Answer: D
10.    Which of the following statements is TRUE?
D1: The decomposition of the schema R(A,B,C) into R1(A,B) and R2(A,C) is always lossless.
D2: The decomposition of the schema R(A,B,C,D,E) having AD→B, C→DE, B→AE, AE→C into R1(A,B,D) and R2(A,C,D,E) is lossless.
(A) Both D1 and D2      (B) Neither D1 and D2
(C) Only D1                   (D) Only D2
Answer: D


Sunday, 24 July 2016

41.       If S1 is total number of modules defined in the program architecture, S3 is the number of modules whose correct function depends on prior processing then the number of modules not dependent on prior processing is:
(A) 1 + S3/S1                 (B) 1 - S3/S1
(C) 1 + S1/S3                 (D) 1 - S1/S3
Answer: B
42.       The ................ model is preferred for software development when the requirements are not clear.
(A) Rapid Application Development            (B) Rational Unified Process
(C) Evolutionary Model                      (D) WaterfallModel
Answer: C
43.       Which of the following is not included in waterfall model ?
(A) Requirement analysis      (B) Risk analysis
(C) Design                                (D) Coding
Answer: B
44.       The cyclomatic complexity of a flow graph V(G), in terms of predicate nodes is:
(A) P + 1                        (B) P - 1
(C) P - 2                         (D) P + 2
Where P is number of predicate nodes in flow graph V(G).
Answer: A
45.       The extent to which a software tolerates the unexpected problems, is termed as:
(A) Accuracy                 (B) Reliability
(C) Correctness           (D) Robustness
Answer: D

46.       An attacker sits between customer and Banker, and captures the information from the customer and retransmits to the banker by altering the information. This attack is called as ..............
(A) Masquerade Attack           (B) Replay Attack
(C) Passive Attack                   (D) Denial of Service Attack
Answer: B
47.       Consider the following two statements:
(a) Business intelligence and Data warehousing is used for forecasting and Data mining.
(b) Business intelligence and Data warehousing is used for analysis of large volumes of sales data.
Which one of the following options is correct?
(A) (a) is true, (b) is false        (B) Both (a) and (b) are true
(C) (a) is false, (b) is true        (D) Both (a) and (b) are false
Answer: B
48.       Pipelining improves performance by:
(A) decreasing instruction latency
(B) eliminating data hazards
(C) exploiting instruction level parallelism
(D) decreasing the cache miss rate
Answer: C
49.       Consider the following two statements :
(a) Data scrubling is a process to upgrade the quality of data, before it is moved into Data warehouse.
(b) Data scrubling is a process of rejecting data from data warehouse to create indexes.
Which one of the following options is correct ?
(A) (a) is true, (b) is false        (B) (a) is false, (b) is true
(C) Both (a) and (b) are false (D) Both (a) and (b) are true
Answer: A
50.    Given the following statements:
(a) Strategic value of data mining is time stamping
(b) Information collection is an expensive process in building an expert system.
Which of the following options is correct ?
(A) Both (a) and (b) are false (B) Both (a) and (b) are true
(C) (a) is true, (b) is false        (D) (a) is false, (b) is true
Answer: B

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Saturday, 23 July 2016

31.       The number of strings of length 4 that are generated by the regular expression (0|) 1+2* (3|), where | is an alternation character, {+, *} are quantification characters, and is the null string, is:
(A) 08                 (B) 10
(C) 11                 (D) 12
Answer: D
32.       The content of the accumulator after the execution of the following 8085 assembly language program, is:
MVI A, 42H
MVI B, 05H
UGC:      ADD B
DCR B
JNZ UGC
ADI 25H
HLT
(A) 82 H             (B) 78 H
(C) 76 H             (D) 47 H
Answer: C
33.       In .............., the bodies of the two loops are merged together to form a single loop provided that they do not make any references to each other.
(A) Loop unrolling                   (B) Strength reduction
(C) Loop concatenation         (D) Loop jamming
Answer: D
34.       Which of the following is not typically a benefit of dynamic linking?
I. Reduction in overall program execution time.
II. Reduction in overall space consumption in memory.
III. Reduction in overall space consumption on disk.
IV. Reduction in the cost of software updates.
(A) I and IV                    (B) I only
(C) II and III                   (D) IV only
Answer: B
35.       Which of the following is FALSE ?
(A) The grammar S aSb|bSa|SS|, where S is the only non-terminal symbol and is the null string, is ambiguous.
(B) SLR is powerful than LALR.
(C) An LL(1) parser is a top-down parser.
(D) YACC tool is an LALR(1) parser generator.
Answer: B

36.       Consider the reference string
0 1 2 3 0 1 4 0 1 2 3 4
If FIFO page replacement algorithm is used, then the number of page faults with three page frames and four page frames are .......... and ........... respectively.
(A) 10, 9             (B) 9, 9
(C) 10, 10          (D) 9, 10
Answer: D
37.       Suppose there are four processes in execution with 12 instances of a Resource R in a system.
The maximum need of each process and current allocation are given below:
Process
Max. Need
Current Allocation
P1
8
3
P2
9
4
P3
5
2
P4
3
1
With reference to current allocation, is system safe? If so, what is the safe sequence?
(A) No                            (B) Yes, P1 P2 P3 P4
(C) Yes, P4 P3 P1 P2    (D) Yes, P2 P1 P3 P4
Answer: C
38.       If the Disk head is located initially at track 32, find the number of disk moves required with FCFS scheduling criteria if the disk queue of I/O blocks requests are:
98, 37, 14, 124, 65, 67
(A) 320               (B) 322
(C) 321              (D) 319
Answer: C
39.       In UNIX, ............ creates three subdirectories: 'PIS' and two subdirectories 'progs' and ‘data’ from just created subdirectory 'PIS'.
(A) mdkir PIS/progs PIS/data PIS
(B) mkdir PIS progs data
(C) mkdir PIS PIS/progs PIS/data
(D) mkdir PIS/progs data
Answer: C
40.    A scheduling Algorithm assigns priority proportional to the waiting time of a process. Every process starts with priority zero (lowest priority). The scheduler re-evaluates the process priority for every 'T' time units and decides next process to be scheduled. If the process have no I/O operations and all arrive at time zero, then the scheduler implements .............. criteria.
(A) Priority scheduling                        (B) Round Robin Scheduling
(C) Shortest Job First              (D) FCFS
Answer: B

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