Computer Science Questions and Answers

1. A 2MB PCM(pulse code modulation) has 
a) 32 channels 
b) 30 voice channels & 1 signaling channel. 
c) 31 voice channels & 1 signaling channel. 
d) 32 channels out of which 30 voice channels, 1 signaling channel, 
& 1 Synchronization channel.
Ans: (c)

2. Time taken for 1 satellite hop in voice communication is 
a) 1/2 second 
b) 1 seconds 
c) 4 seconds 
d) 2 seconds
Ans: (a)

3. Max number of satellite hops allowed in voice communication is : 
a) only one 
b) more than one 
c) two hops 
d) four hops
Ans: (c)

4. What is the max. decimal number that can be accommodate in a byte. 
a) 128 
b) 256 
c) 255 
d) 512
Ans: (c)
 
5. Conditional results after execution of an instruction in a micro processor 
is stored in 
a) register 
b) accumulator 
c) flag register 
d) flag register part of PSW(Program Status Word)

Ans: (d)

6. Frequency at which VOICE is sampled is 
a) 4 Khz 
b) 8 Khz 
c) 16 Khz 
d) 64 Khz
Ans: (a)

7. Line of Sight is  
 a) Straight Line 
b) Parabolic  
c) Tx & Rx should be visible to each other 
d) none
Ans: (c)

8. Purpose of PC (Program Counter) in a Micro Processor is 
a) To store address of TOS (Top of Stack) 
b) To store address of next instruction to be executed. 
c) Count the number of instructions. 
d) To store base address of the stack.
Ans: (b)

9. What action is taken when the processor under execution is interrupted by  a non-mask able interrupt? 
a) Processor serves the interrupt request after completing the execution of the
 current instruction. 
b) Processor serves the interrupt request after completing the current task. 
c) Processor serves the interrupt request immediately. 
d) Processor serving the interrupt request depends upon the priority of the current
 task under execution.
Ans: (a)

10. The status of the Kernel is 
a) task 
b) process 
c) not defined. 
d) None of the above.
Ans: (b)

11. To send a data packet using datagram, connection will be established 
a) before data transmission. 
b) Connection is not established before data transmission. 
c) No connection is required. 
d) None of the above.
Ans: (c)
 
12. Word alignment is 
a) aligning the address to the next word boundary of the machine. 
b) Aligning to even boundary. 
c) Aligning to word boundary. 
d) None of the above.
Ans: (a)

13. When a 'C' function call is made, the order in which parameters passed to the function are pushed into the stack is 
a) left to right 
b) right to left 
c) bigger variables are moved first than the smaller variables. 
d) Smaller variables are moved first than the bigger ones. 
e) None of the above.
Ans: (b)

14. What is the type of signaling used between two exchanges? 
a) inband 
b) common channel signaling 
c) any of the above 
d) none of the above.
Ans: (a)

15.Buffering is  
a) the process of temporarily storing the data to allow for small variation in  device speeds 
b) a method to reduce cross talks 
c) storage of data within transmitting medium until the receiver is ready
 to receive. 
d) a method to reduce routing overhead.
Ans: (a)
 
16. Memory allocation of variables declared in a program is 
 a) allocated in RAM. 
b) Allocated in ROM. 
c) allocated on stack. 
d) Assigned to registers.
Ans: (c)
 
17. A software that allows a personal computer to pretend as a computer terminal is  
a) terminal adapter 
b) bulletin board 
c) modem 
d) terminal emulation
Ans: (d)

18. Find the output of the following program
int *p,*q; 
p=(int *)1000; 
q=(int *)2000; 
printf("%d",(q-p)); 
Ans: 500
 
19. Which addressing mode is used in the following statements:
(a) MVI B, 55  
(b) MOV B,A  
(c) MOV M,A
Ans. (a) immediate addressing mode. 
(b) Register Addressing Mode 
(c) Direct addressing mode
 
20. RS-232C standard is used in _____________.
Ans. Serial I/O

21. Memory. Management in Operating Systems is done by 
a) Memory Management Unit 
b) Memory management software of the Operating System 
c) Kernel
Ans: (b)
 
22. What is done for a Push operation?
Ans: SP is decremented and then the value is stored.

23. Binary equivalent of 52 
 Ans. 110100 
 24. Hexadecimal equivalent of 3452 
 Ans. 72A 
  
25. Explain Just In Time Concept? 
 Ans. Elimination of waste by purchasing manufacturing exactly when needed 
  
26. A good way of unit testing s/w program is 
 Ans. User test 
  
27. OOT uses 
 Ans. Encapsulated of detect methods 
  
28.EDI useful in 
 Ans. Electronic Transmission 
  
29. MRPII different from MRP 
 Ans. Modular version of man redundant initials 
  
30. Hard disk time for R/W head to move to correct sector 
 Ans. Latency Time 
  
31. The percentage of times a page number bound in associate register is called 
 Ans. Bit ratio 
  
32. Expand MODEM 
Ans. Modulator and Demodulator 
  
33. RDBMS file system can be defined as 
 Ans. Interrelated 
  
34. Super Key is 
Ans. Primary key and Attribute 
  
35. Windows 95 supports 
(a) Multi-user  
(b) n tasks  
(c) Both 
(d) None 
Ans. (a) 
 
 36.In the command scanf, h is used for  
 Ans. Short int 
  
37.A process is defined as 
Ans. Program in execution 
  
38.A thread is 
Ans. Detachable unit of executable code) 
  
39.What is the advantage of Win NT over Win 95  
Ans. Robust and secure 
 
40.How is memory management done in Win95  
Ans. Through paging and segmentation 
 
41.What is meant by polymorphism 
Ans. Redefinition of a base class method in a derived class 
  
42.What is the essential feature of inheritance  
Ans. All properties of existing class are derived 
  
43.What does the protocol FTP do 
Ans. Transfer a file b/w stations with user authentication 
  
44.In the transport layer ,TCP is what type of protocol 
Ans. Connection oriented 
  
45.Why is a gateway used  
Ans. To connect incompatible networks 
  
46.How is linked list implemented 
Ans. By referential structures 
  
47.What method is used in Win95 in multitasking 
Ans. Non preemptive check 
  
48.What is a semaphore  
Ans. A method synchronization of multiple processes 
  
49.What is the precedence order from high to low ,of the symbols ( ) ++ /  
Ans.( ) , ++, / 
 
50.Preorder of A*(B+C)/D-G 
Ans.*+ABC/-DG 
 
51.What is the efficiency of merge sort  
Ans. O(n log n) 
  
52.In which layer are routers used  
Ans.In network layer  
  
53.Which of the following sorting algorithm has average sorting behavior -- Bubble sort,merge sort,heap sort,exchange sort 
Ans. Heap sort 
  
54.In binary search tree which traversal is used for getting ascending order values--Inorder ,postorder,preorder 
 Ans.Inorder 
  
55.What are device drivers used for  
 Ans.To provide software for enabling the hardware 
  
56.What is fork command in unix  
 Ans. System call used to create process 
 
 57.What is make command in unix 
 Ans. Used for creation of more than one file 
  
58.In unix .profile contains  
 Ans. Start up program 
  
59.In unix 'ls 'stores contents in 
 Ans.inode block

 60. Which of the following involves context switch,
(a) system call  
(b) priviliged instruction 
(c) floating poitnt exception 
(d) all the above 
(e) none of the above
Ans: (a)
 
61. In OST, terminal emulation is done in
(a) sessions layer  
(b) application layer  
(c) presentation layer  
(d) transport layer
Ans: (b)

62. For 1 MB memory, the  number of address lines required,
(a)11  
(b)16  
(c)22  
(d) 24
Ans. (b)

63. Semaphore is used for
(a) synchronization  
(b) dead-lock avoidence 
(c) box  
(d) none
Ans. (a)

64. Which holds true for the following statement
     class c: public A, public B
a) 2 member in class A, B should not have same name 
b) 2 member in class A, C should not have same name 
c) both  
d) none
Ans. (a)

65.Preprocessor.. does not do which one of the following
(a) macro 
(b) conditional complication 
(c) in type checking  
(d) including load file
Ans. (c)
 
66. Piggy backing is a technique for
a) Flow control  
b) Sequence  
c) Acknowledgement  
d) retransmission
Ans. (c)

67. Which is not a memory management scheme?
a) buddy system 
b) swapping 
c) monitors 
d) paging 
Ans : c

68. There was a circuit given using three NAND gates with two inputs and one output. 
    Find the output.
a) OR 
b) AND 
c) XOR 
d) NOT
Ans. (a)

69.I integrated check value(ICV) are used as:
Ans. The client computes the ICV and then compares it with the senders value.

70. When applets are downloaded from web sites , a byte verifier performs _________?
Ans. Status check.

71. An IP/IPX packet received by a computer using... having IP/IPX  both 
how the packet is handled.
Ans. Read the, field in the packet header with to send IP or IPX protocol.

72. The UNIX shell ....
a) does not come with the rest of the system 
b) forms the interface between the user and the kernal 
c) does not give any scope for programming 
d) deos not allow calling one program from with in another 
e) all of the above
Ans. (b)

73. In UNIX a files i-node ......?
Ans. Is a data structure that defines all specifications of a file like the file size,  
        number of lines to a file, permissions etc.

74. The very first process created by the kernel that runs till the kernel 
process is halts is
a) init 
b) getty 
c) both (a) and (b) 
d) none of these
Ans. (a)

75. In the process table entry for the kernel process, the process id value is
(a) 0  
(b) 1  
(c) 2  
(d) 255  
(e) it does not have a process table entry
Ans. (a)

 
76. Which of the following API is used to hide a window
a) ShowWindow 
b) EnableWindow 
c) MoveWindow 
d) SetWindowPlacement 
e) None of the above
Ans. (a)

77. Which function is the entry point for a DLL in MS Windows 3.1
a) Main 
b) Winmain 
c) Dllmain 
d) Libmain 
e) None
Ans. (b)

78. The standard source for standard input, standard output and standard error is
a) the terminal 
b) /dev/null 
c) /usr/you/input, /usr/you/output/, /usr/you/error respectively 
d) None
Ans. (a)

79. The redirection operators > and >>
a) do the same function 
b) differ : > overwrites, while >> appends 
c) differ : > is used for input while >> is used for output 
d) differ : > write to any file while >> write only to standard output 
e) None of these
Ans. (b)

80. The command grep first second third /usr/you/myfile
a) prints lines containing the words first, second or third from the 
file /usr/you/myfile 
b) searches for lines containing the pattern first in the files 
second, third, and /usr/you/myfile and prints them 
c) searches the files /usr/you/myfiel and third for lines containing the 
words first or second and prints them 
d) replaces the word first with the word second in the files third 
and /usr/you/myfile 
e) None of the above
Ans. (b)

81. You are creating a Index on EMPNO column in the EMPLOYEE table. 
Which statement will you use? 
a) CREATE INdEX emp_empno_idx ON employee, empno; 
b) CREATE INdEX emp_empno_idx FOR employee, empno; 
c) CREATE INdEX emp_empno_idx ON employee(empno);  
d) CREATE emp_empno_idx INdEX ON employee(empno); 
 Ans. c
 
82. Which program construct must return a value? 
a) Package 
b) Function  
c) Anonymous block 
d) Stored Procedure 
e) Application Procedure 
 Ans. b
 
83. Which Statement would you use to remove the EMPLOYEE_Id_PK PRIMARY KEY 
constraint and all depending constraints fromthe EMPLOYEE table? 
a) ALTER TABLE employee dROP PRIMARY KEY CASCAdE;  
b) ALTER TABLE employee dELETE PRIMARY KEY CASCAdE; 
c) MOdIFY TABLE employee dROP CONSTRAINT employee_id_pk CASCAdE; 
d) ALTER TABLE employee dROP PRIMARY KEY employee_id_pk CASCAdE; 
e) MOdIFY TABLE employee dELETE PRIMARY KEY employee_id_pk CASCAdE; 
 Ans. a
 
84. Which three commands cause a transaction to end? (Chosse three) 
a) ALTER 
b) GRANT  
c) DELETE 
d) INSERT 
e) UPdATE 
f) ROLLBACK 
Ans. a ,b ,f

85. Under which circumstance should you create an index on a table? 
a) The table is small. 
b) The table is updated frequently. 
c) A columns values are static and contain a narrow range of values 
d) Two columns are consistently used in the WHERE clause join condition of SELECT  
     statements. 
 Ans.d

86. What was the first name given to Java Programming Language.  
 a) Oak - Java 
b) Small Talk 
c) Oak 
d) None 
Ans.a