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.

Sunday, 18 March 2018

71.       You are given four images represented as
The value of entropy is maximum for image
(A) I1                   (B) I2
(C) I3                   (D) I4
Answer: C
Entropy of image represent the randomness pixels.
In I1 all pixel are same. Entropy is zero. In I3 two are same therefore, entropy is maximum whereas in I2 and I4 three3 are same.
72.       A cryptarithmetic problem of the type
Can be solved efficiently using
(A) depth first technique
(B) breadth first technique
(C) constraint satisfaction technique
(D) bidirectional technique
Answer: C
73.       Match the following :
List - I
a. Supervised learning
b. Unsupervised learning
c. Reinforcement learning
d. Inductive learning
List - II
1. The decision system receives rewards for its action at the end of a sequence of steps.
2. Manual labels of inputs are not used.
3. Manual labels of inputs are used.
4. System learns by example
Codes :
      a   b   c   d
(A) 1   2   3   4
(B) 2   3   1   4
(C) 3   2   4   1
(D) 3   2   1   4
Answer: D
74.       A* algorithm is guaranteed to find an optimal solution if
(A) h' is always 0.
(B) g is always 1.
(C) h' never overestimates h.
(D) h' never underestimates h.
Answer: C
75.       Let θ(x, y, z) be the statement “x+y=z” and let there be two quantifications given as
(i) x y Z θ(x, y, z)
(ii) Z x y θ(x, y, z)
Where x, y, z are real numbers. Then which one of the following is correct?
(A) (i) is true and (ii) is true.
(B) (i) is true and (ii) is false.
(C) (i) is false and (ii) is true.
(D) (i) is false and (ii) is false.
Answer: B


Saturday, 17 March 2018

61.       Which one is a collection of templates and rules?
Answer: D
XSL is a language for expressing style sheets. An XSL style sheet is, like with CSS, a file that describes how to display an XML document of a given type. XSL shares the functionality and is compatible with CSS2 (although it uses a different syntax).
62.       A program P calls two subprograms P1 and P2. P1 can fail 50% times and P2 40% times. Then P can fail
(A) 50%
(B) 60%
(C) 10%
(D) 70%
Answer: D
1 - (1 - 0.5)(1 - 0.4) = 1 - 0.3 = 0.7 = 70%
63.       Third normal form is based on the concept of ………….
(A) Closure Dependency
(B) Transitive Dependency
(C) Normal Dependency
(D) Functional Dependency
Answer: B
64.       If the Fourier transform of the function f(x, y) is F(m, n), then the Fourier transform of the function f(2x, 2y) is :
Answer: A
65.       …………… establishes information about when, why and by whom changes are made in a software.
(A) Software Configuration Management.
(B) Change Control.
(C) Version Control.
(D) An Audit Trail.
Answer: D
66.       Match the following with respect to HTML tags and usage.
List - I
b. EM
c. VAR
List - II
1. Italic representation
2. Represents output from programmes
3. Represents to other source
4. Argument to a programme
Codes :
      a   b   c   d
(A) 3   1   4   2
(B) 2   3   1   4
(C) 4   2   3   1
(D) 1   3   4   1
Answer: A
The <cite> tag defines the title of a work (e.g. a book, a song, a movie, etc.). The cite attribute specifies the source of a quotation.
The <em> tag is a phrase tag. It renders as emphasized text. Browsers, by default, italicize the text found within the <em> tag.
The <var> tag is a phrase tag. It defines a variable.
The samp element represents (sample) output from a program or computing system.
67.       An expert system shell is an expert system without
(A) domain knowledge
(B) explanation facility
(C) reasoning with knowledge
(D) all of the above
Answer: A
68.       An example of a dictionary-based coding technique is
(A) Run-length coding
(B) Huffman coding
(C) Predictive coding
(D) LZW coding
Answer: D
LZW is a "dictionary"-based compression algorithm. This means that instead of tabulating character counts and building trees (as for Huffman encoding), LZW encodes data by referencing a dictionary. Thus, to encode a substring, only a single code number, corresponding to that substring's index in the dictionary, needs to be written to the output file.
Typically, you can expect LZW to compress text, executable code, and similar data files to about one-half their original size.
69.       Which is the method used to retrieve the current state of a check box?
(A) get State()
(B) put State()
(C) retrieve State()
(D) write State()
Answer: A
70.    Referential integrity is directly related to
(A) Relation key
(B) Foreign key
(C) Primary key
(D) Candidate key
Answer: B

Friday, 16 March 2018

51.       Suppose there are logn sorted lists of n/logn elements each. The time complexity of producing a sorted list of all these elements is (use heap data structure)
(A) O(n log logn)
(B) θ(n logn)
(C) Ω(n logn)
(D) Ω(n3/2)
Answer: A
We can merge m arrays of each size n in in O(MN*LogN) time using Min Heap.
M = n/Logn
N = Logn
The time complexity = O(n/Logn * Logn * Log Log n) = O(nLogLogn)
52.       Consider the program below in a hypothetical programming language which allows global variables and a choice of static or dynamic scoping
int i;
program Main()
call f();
procedure f()
int i=20;
call g();
procedure g()
print i;
Let x be the value printed under static scoping and y be the value printed under dynamic scoping. Then x and y are
(A) x=10, y=20
(B) x=20, y=10
(C) x=20, y=20
(D) x=10, y=10
Answer: D
53.       If the parse tree of a word w generated by a Chomsky normal form grammar has no path of length greater than i, then the word w is of length
(A) no greater than 2i+1
(B) no greater than 2i
(C) no greater than 2i–1
(D) no greater than i
Answer: C
54.       The Object Modelling Technique (OMT) uses the following three kinds of model to describe a system
(A) Class Model, Object Model and Analysis Model.
(B) Object Model, Dynamic Model, and Functional Model.
(C) Class Model, Dynamic Model and Functional Model.
(D) Object Model, Analysis Model and Dynamic Model.
Answer: B
55.       The factors that determine the quality of a software system are
(A) correctness, reliability
(B) efficiency, usability, maintainability
(C) testability, portability, accuracy, error tolerances, expandability, access control, audit.
(D) All of the above
Answer: D

56.       If a relation with a Schema R is decomposed into two relations R1 and R2 such that (R1ᴗR2)=R1 then which one of the following is to be satisfied for a lossless joint decomposition (→ indicates functional dependency)
(A) (R1∩R2)→R1 or R1∩R2→R2
(B) R1∩R2→R1
(C) R1∩R2→R2
(D) R1∩R2→R1 and R1∩R2→R2
Answer: A
Let R be a relation schema.
Let F be a set of functional dependencies on R.
Let R1 and R2 form a decomposition of R.
The decomposition is a lossless-join decomposition of R if at least one of the following functional dependencies are in F+
1.  R1∩R2→R1
2.  R1∩R2→R2
57.       Given the following statements :
(i) Recursive enumerable sets are closed under complementation.
(ii) Recursive sets are closed under complementation.
Which is/are the correct statements?
(A) only (i)
(B) only (ii)
(C) both (i) and (ii)
(D) neither (i) nor (ii)
Answer: B
58.       Skolemization is the process of
(A) bringing all the quantifiers in the beginning of a formula in FDL.
(B) removing all the universal quantifiers.
(C) removing all the existential quantifiers.
(D) all of the above.
Answer: C
59.       Which level of Abstraction describes how data are stored in the data base?
(A) Physical level
(B) View level
(C) Abstraction level
(D) Logical level
Answer: A
60.    The transform which possesses the “multi-resolution” property is
(A) Fourier transform
(B) Short-time-Fourier transform
(C) Wavelet transform
(D) Karhunen-Loere transform
Answer: C

Thursday, 15 March 2018

41.       Consider a system having m resources of the same type. These resources are shared by 3 processes A, B and C which have peak demands of 3, 4 and 6 respectively. For what value of m deadlock will not occur?
(A) 7
(B) 9
(C) 10
(D) 13
Answer: D
42.       The grammar ‘G1’ S→OSO|ISI|0|1|ϵ and the grammar ‘G2’ is
S→aS|aSb|X, X→Xa|a.
Which is the correct statement?
(A) G1 is ambiguous, G2 is unambiguous
(B) G1 is unambiguous, G2 is ambiguous
(C) Both G1 and G2 are ambiguous
(D) Both G1 and G2 are unambiguous
Answer: B
43.       Consider n processes sharing the CPU in round robin fashion. Assuming that each process switch takes s seconds. What must be the quantum size q such that the overhead resulting from process switching is minimized but, at the same time each process is guaranteed to get its turn at the CPU at least every t seconds?
Answer: B
44.       The Default Parameter Passing Mechanism is called as
(A) Call by Value
(B) Call by Reference
(C) Call by Address
(D) Call by Name
Answer: A
45.       Which of the following regular expression identities are true?
(A) (r+s)*=r*s*
(B) (r+s)*=r*+s*
(C) (r+s)*=(r*s*)*
(D) r*s*=r*+s*
Answer: C

46.       Two graphs A and B are shown below :
Which one of the following statement is true?
(A) Both A and B are planar.
(B) Neither A nor B is planar.
(C) A is planar and B is not.
(D) B is planar and A is not.
Answer: A
A planar graph is a graph that can be embedded in the plane, i.e., it can be drawn on the plane in such a way that its edges intersect only at their endpoints. In other words, it can be drawn in such a way that no edges cross each other.
47.       The minimum number of states of the non-deterministic finite automation which accepts the language
{ababn|n≥0}U{aban|n≥0} is
(A) 3
(B) 4
(C) 5
(D) 6
Answer: C
48.       Functions defined with class name are called as
(A) Inline function
(B) Friend function
(C) Constructor
(D) Static function
Answer: C
49.       Let f be the fraction of a computation (in terms of time) that is parallelizable, P the number of processors in the system, and sp the speed up achievable in comparison with sequential execution – then the sp can be calculated using the relation :
Answer: C
50.    Which of the following definitions generates the same Language as L, where L={WWR|Wϵ{a,b}*}
(A) S→asb|bsa|ϵ
(B) S→asa|bsb|ϵ
(C) S→asb|bsa|asa|bsb|ϵ
(D) S→asb|bsa|asa|bsb
Answer: B