Computer Science & Computer Applications Questions and Answers

1. A method of providing security to transport e-mails is

Ans.  PGP

2. A combinational circuit is designed to take 4 bit input. The number from 0 to 9 are given as input in the binary form. The circuit outputs ‘1’ if 5,6,7 or 9 are given input.For all other numbers the circuit outputs ‘0’. The circuit is designed only using AND, OR, NOT gates. What is the minimum number of gates required ?

Ans.  3

3. The MAC protocol used in Ethernet is

Ans. CSMA/CD

4. The simplified form of the Boolean expression (X+Y’+Z) (X+Y’+Z’) (X+Y+Z)

Ans.  X+Y’Z

5. Arrange the following IP addresses in the order of Class A, Class B, Class C and Class D.

I. 193. 200. 151. 2

II. 189. 51. 21. 200

III. 225. 2. 2. 200

IV. 126. 8. 2. 200

Ans.  IV, II, I, III

6. Addressing modes of the following 8085 instructions in the same order.

LDA, LXI, ADD r1, r2, MOV A,M

Ans. Direct, Immediate, Register, Indirect

7. The concatenation of two lists is to be performed in 0(1) time. Which of the following implementation of a list should be used?

Ans.  Circularly doubly linked list

8. Match the following :

I. Non vectored interrupt   1. ISR

II. Non Maskable interrupt 2. RST2

III. Program for interrupt  3. TRAP

IV. Software Interrupt        4. INTR

          I   II  III  IV

Ans.    4  3    1    2

9. Search algorithms are Judged on the basis of

I. Completeness

II. Optimality

III. Time complexity

IV. Space complexity

(A) I and II

(B) I, II and III

(C) II, III and IV

Ans.  All of the above

10. Choose the answer from the following register(s) that store the address of a memory location.

I. Program counter

II. Accumulator

III. MAR

IV. BC Register pair

Ans.  I and III are correct

11. If G be a complete undirected graph on 6 vertices. If vertices of G are labeled then the number of distinct cycles of length 4 in G is equal to

Ans.  90

12. The number of vectored interrupts in 8085 is

Ans.  4

13. The Java compiler translates source code into

Ans.  Byte Code

14. Object-Modelling Technique was proposed by

Ans.  Rambaugh

15. The following scheduling algorithm is inherently pre emptive

Ans.  Round Robin

16. An Abstract Data Type (ADT) is

Ans.  a data type for which only the operations defined on it can be used

17. In a paged memory the page hit ratio is 0.35. The time required to access a page in secondary memory is equal to 100 nsec. The time required to access a page in primary memory is 10 nsec. The average time equired to access a page is

Ans.  68.5 nsec.

18. ______________ abstraction is a named sequence of instructions that has a specific and limited function.

Ans.  Procedural

19. A process executes the code

fork ( ) ;

fork ( ) ;

fork ( ) ;

fork ( ) ;

The total number of child processes created is

Ans.  15

20. If A = { 0, 1 }, then the number of possible strings of length ‘n’ is

Ans. 2ⁿ

21. The overlay tree for a program is given below. What will be the size of the physical memory partition required to load and run the program?

Ans. 14KB

22. The complexity of inter connection among modules is described by

Ans.  Coupling

23. A 1000 K byte memory is managed using variable partitions but to compaction. It currently has two partitions of sizes 200 K bytes and 340 K bytes respectively. The smallest allocation request in K bytes that

could be denied is for

Ans. 461

24. The grammar guaranteed by production rules

S->a SBc, CB->BC, aB ->aa is

Ans. aⁿ bⁿ cⁿ, n>0

25. The following page replacement algorithms suffer from Belady’s anomaly.

I. Optimal replacement

II. LRU

III. FIFO

IV. MRU

Ans.  I and III correct

26. Given the basic ER and relational models, which of the following is INCORRECT?

A) An attribute of an entity can have more than one value

(B) An attribute of an entity can be composite

(C) In a row of a relational table, an attribute can have more than one value

(D) In a row of a relational table, an attribute can have exactly one value or a NULL value

Ans( C).  In a row of a relational table, an attribute can have more than one value

27. The algorithm used for searching AND-OR graph is

Ans.  AO*

28. The PROJECT operator of a relational algebra creates a new table that has always

Ans.  Same number of rows as the original table

29. The Natural Language sentence will be represented in NLP with

I. ATN

II. RTN

III. FPL

IV. FRAMES

Ans.  I, II

30. The file organization in which the physical location of a record is determined by a Mathematical function that maps the key to address of the record is

Ans.  Hashed file organization

31. Consider the following statements about the cyclomatic complexity of the control flow graph of a program module. Which of these are TRUE ?

i. The cyclomatic complexity of a module is equal to the maximum number of linearly independent circuits in the graph.

ii. The cyclomatic complexity of a module is the number of decisions on the module plus one. Where a ecision is effectively any conditional statement in the module.

iii. The cyclomatic complexity can also be used as a number of linearly independent paths that should be

tested during path coverage testing

Ans. i, ii and iii

32. Which of the sorting algorithm is the slowest?

Ans.  Bubble sort

33. The approach used in top-down analysis and design is

Ans.  to identify a top level function and then create a hierarchy of lower level modules and components

34. Match the following:

I. Flow control                  1. Token Bucket

II. Error control                2. Sliding window

III. Congestion control      3. Manchester encoding

IV. Synchronization                    4. Parity bit

         I    II   III   IV

Ans.  2    4    1    3

35. Slow start is a technique used by the TCP to reduce

Ans. Number of time outs of segments

36. A B-Tree used as an index for a large database table has four levels including root node. If a new key is inserted in this index, then the maximum number of nodes that could be newly created in the process are

Ans.  5

37. Consider the following proportional statements

P1: ((A^B)->C)=((A->C)^(B->C))

P2:((AvB)->C)=((A->C)v(B->C))

Which one of the following are true?

(D) Both P1 and P2 are not tautologies

38. What is difference between a Java applet and a Java application ?

(A) An application can in general be trusted whereas an applet can’t

(B) An applet must be executed in a browser environment

(C) An applet is not able to access the files of the computer it runs on

Ans.  All of the above

39. The following machine will accept the String

Ans.  bab

40. Types of validation testing

Ans.  Alpha and Beta Testing

41. Choose the correct answer, the protocol which returns IP address.

I. ARP

II. RARP

III. HTTP

IV. DNS

Ans.  II and IV correct

42. Assuming P !=N which of the following is TRUE ?

Ans.  NP – complete nP = φ

43. What is the appropriate pairing of items in the two columns, listing various activities encountered in a software life cycle ?

P. Requirements      1. Module capture Development and Integration

Q. Design               2. Domain analysis

R. Implementation  3. Structural Behavioural Modelling

S. Maintenance       4. Performance Tuning

Ans. P – 2, Q – 3, R – 1, S – 4

44. In UNIX, when the read system call encounters EOF, it returns

Ans.  –1

45. Which of the following regular expression identities are true ?

Ans.  (r’)¹ = r

46. The message 11001001 is to be transmitted using the CRC polynomial x3 + 1 to protect it from errors. The message that should be transmitted is

Ans.  110010010011

47. _______________ is black box testing method.

Ans.  Boundary value analysis

48. If the hamming distance is ‘m’ then the number of errors that can be corrected is

Ans.  Less than m/2

49. What is the maximum number of I/O devices that can be interfaced to 8085 ?

Ans. 256

50. Compression Ratio is defined as

Ans. compressed size/uncompressed size)

51. Neural Networks are models of

Ans.  Biological nervous systems

Question No.’s 52 and 53

Disk requests come to a disk drive for cylinders 10, 22, 20, 2, 40, 6 and 36 in that order at a time when the disk drive is reading from cylinder 20. The seek time is 6 ms per cylinder. The disk can be rotated either clockwise or counter clockwise.

52. The total seek time if the disk arm scheduling algorithm is first-cum-first served.

Ans. 876 msec.

53. If the scheduling algorithm is closest cylinder next, then the total will be

Ans.  360 msec.

Question No.’s 54, 55 and 56

The next three questions are based on Huffman’s coding for the symbol A with probability 0.3, B with 0.15, C with 0.1, D with 0.25 and E with 0.2.

54. The minimum number of bits required to represent B is

Ans. 3

55. The minimum number of bits required to represent all the symbols together is

Ans. 12

56. The average code length of the given problem is

Ans. 2.25

57. Character Recognition is application of

Ans.  Neural Networks

58. Inference Engine consists of

I. Facts

II. User Interface

III. Search

IV. Domain Expert

Ans.  I, III

59. With regarding to exceptions following is TRUE

Ans.  Raised by program and OS

60. Which of the following concurrency control protocols ensure both conflict serializability and freedom from dead deadlock

I. 2 – phase locking

II. Time-stamp ordering

Ans. II only

61. The following system calls are related to file operations in UNIX

I. Signal

II. Kill

III. Seek

IV. Unlink

Ans.  III and IV correct

62. HTML (Hyper Text Markup Language) has language elements which permit certain actions other than describing the structure of the web document. Which one of the following actions is not supported by pure

HTML (without any server or client side scripting) pages?

Ans.  Display the client time as part of the page

63. Search engine is a ____________ agent.

Ans. Intelligent

64. The commonly used UNIX commands like date, ls, cut etc. are stored in

Ans.  / bin and /usr/bin directory

65. ADO stands for

Ans.  Active × Data Object

66. If f is a linear transformation from the plane to the real numbers and if f(1, 1) = 1 and f(–1, 0) = 0 then        f (3, 5) =

Ans. 9

67. Fuzzy Logic is proposed by

Ans.  ZADEH

68. If the inorder and postorder traversal results of a binary tree are A, C, B, F, E, D, G and A, B, C, E, G, D, F respectively. Identify the root node of it.

Ans. F

69. NLP includes problems

(A) in which the objective function is linear but some constraints are not linear

(B) in which the constraints are linear but the objective function is not linear

(C) in which both the objective function and all the constraints are not linear

Ans.  all of the above

70. Class C is inherited from Class A and Class B, Class D is inherited from Class C Which of the following is true ?

I. Class C inherits Class A attributes

II. Class C inherits Class B attributes

III. Class D inherits Class B attributes only

IV. Class D inherits Class A attributes only

Ans.  I, II

71. Which of the following is an assertion ?

Ans.  P is true, P and Q are true and K or not (Q) is true implies K is true

72. In 8085, the addressing mode used for LDAX rp instruction is

Ans.  Indirect

73. Given an arbitrary Non-deterministic Finite Automation (NFA) with N states, the maximum number of states in an equivalent minimized DFA is atleast

Ans. N!

74. The maximum packet size of IPV4 is

Ans. 65535 bytes

75. Which of the following statements are TRUE about an SQL query ?

P : An SQL query can contain a HAVING clause even if it doesnot have a GROUP by clause.

Q : An SQL query can contain a HAVING clause only if it has GROUP by clause.

R : All attributes used in the GROUP by clause must appear in the SELECT clause.

S : Not all attributes used in the GROUP by clause need to appear in the SELECT clause.

Ans.  P and S