## TNPSC-2012-Polytechnic-CS

 Question 1
Which of the following computers is least powerful?
 A Mini B Micro C Mainframe D Super
Question 1 Explanation:
Micro computer is the least powerful computer and super computer is the most powerful computer.
 Question 2
The technique which repeatedly uses the same block of internal storage during different stages of problem is called
 A Overlay B Overlapping C Swapping D Reuse
Operating-Systems       Memory-Management
Question 2 Explanation:
In a general computing sense, overlaying means "the process of transferring a block of program code or other data into main memory, replacing what is already stored". Overlaying is a programming method that allows programs to be larger than the computer's main memory.
 Question 3
The number of instructions needed to add n numbers and store the result in memory using only one address instruction is
 A n B n+1 C n-1 D independent of n
Computer-Organization       Machine-Instructions
Question 3 Explanation:
At first instruction we will load the first no. in accumulator and then from second instruction we will add remaining n-1 no. using accumulator. Till now n instruction is used. And finally we will use one more instruction to store the result back to memory. So in total n+1 instruction is required.
 Question 4
The most relevant addressing mode to write position independent code is
 A Direct mode B Indirect mode C Relative mode D Indexed mode
Question 4 Explanation:
Relative mode is the most relevant addressing mode to write position independent code.
Indexed mode is for arrays and structure.
Indirect mode is used for pointers.
 Question 5
The CPU of a computer takes instruction from the memory and executes them. This process is called
 A Load cycle B Time sequences C Fetch-execute cycle D Clock cycle
Computer-Organization       Machine-Instructions
Question 5 Explanation:
The process in which a CPU of a computer takes instruction from memory and executes them is called fetch-execute cycle.
 Question 6
A five figure number is formed by the digits 0, 1, 2, 3, 4 without repetition. Then probability that the number formed is divisible by 4 in
 A 3/15 B 5/16 C 7/16 D 9/16
Engineering-Mathematics       Probability
 Question 7
If A and B be sets with cardinalities m and n respectively, then number of one-one mappings (injections) from A to B, when m < n, is
 A mn B nPm C nCm D None of these
Engineering-Mathematics       Relations-and-Functions
Question 7 Explanation:
The formula for above given question is nPm.
 Question 8
The set of all nth roots of unity under multiplication of complex numbers form a/an
 A Semi-group with identity B Communicative semi groups with identity C Group D Abelian group
Engineering-Mathematics       Set-Theory
Question 8 Explanation:
More generally, if C is a group and z∈C with zn = 1, where 1 is the identity of C, then G = {1,z,z2,...,zn-1} is a group (actually, a subgroup of C).
Indeed:
• Closure: zjzk = zj+k = zr ∈ G, where r = (j+k) mod n.
• Associativity: comes from C.
• Identity: 1 ∈ G by definition, and 1 is the identity of C.
• Inverse: zjzn-j = 1.
• Commutativity: zjzk = zj+k = zk+j = zkzj.
 Question 9
How many 10 digit numbers can be written by using the digits 1 and 2?
 A 10 C1 + 9 C2 B 210 C 10 C2 D 10 1
Engineering-Mathematics       Combinatorics
Question 9 Explanation:
For each digit we have two choices ‘1 or 2’. So no. of possible 10 digits nos.
2*2*2*2*2*2*2*2*2*2 = 210
 Question 10
T is a graph with n vertices. T is connected and has exactly n – 1 edges. Then
 A T is a tree B T contains no cycles C Every pair of vertices in T is connected by exactly one path D Addition of a new edge will create a cycle
Engineering-Mathematics       Graph-Theory
Question 10 Explanation:
Any graph with n vertices and n-1 edges which is connected will definitely be a tree.
 Question 11
Eigenvectors of a real symmetric matrix corresponding to different eigenvalues are
 A Orthogonal B Singular C Non-singular D None of these
Engineering-Mathematics       Linear-Algebra
Question 11 Explanation:
Eigen-vectors of a real symmetric matrix corresponding to different eigenvalues are orthogonal to each other.
 Question 12
If L1 and L2 are context free language and R is a regular set. Which one of the languages below is not necessarily a context free language?
 A L1L2 B L1∩L2 C L1∪R D L1∪L2
Theory-of-Computation       Regular-Language
Question 12 Explanation:
Context free language is not closed under intersection. Hence B is the correct option.
 Question 13
CSG can be recognized by
 A push-down automata B 2 way linear bounded automaton C finite state automata D none of these
Theory-of-Computation       Context-Sensitive-Grammar
Question 13 Explanation:
Context sensitive grammar can be recognized by linear bounded automata.
 Question 14
Consider the following grammar:
```S → Ax |By
A → By|Cw
B → x|Bw
C → y ```
Which of the regular expressions describes the same set of strings as the grammar?
 A xw+y+xw*yx+ywx B xwy+xw*xy*ywx C xw*y+xw*yx+ywx D xwxy+xww*yywx
Theory-of-Computation       Regular-Expression
Question 14 Explanation:
Option A do not contain xy which is generated by the grammar.
Option B do not contain xy which is generated by the grammar.
Option C do not contain xy which is generated by the grammar.
 Question 15
Recursively enumerable languages are not closed under
 A Union B Intersection C Complementation D Concatenation
Theory-of-Computation       Recursive-and-Recursively-Enumerable-Language
Question 15 Explanation:
Recursively enumerable language are not closed under complementation.
 Question 16
Turing machine is more powerful than FMs because
 A Tape movement is confined to one direction B It has no finite state C It has the capability to remember arbitrarily long sequences of input symbols D None of these
Theory-of-Computation       Turing-machines
Question 16 Explanation:
Turing machines is more powerful than finite machines because it has the capability to remember arbitrarily long sequences of input symbols.
 Question 17
Which of the following statements is wrong?
 A The language accepted by finite automata is the languages denoted by regular expressions. B For every DFA there is a regular expression denoting its language C For a regular expression r, there does not exist any NFA with transit that accepts L(r) D None of these
Theory-of-Computation       Finite-Automata
Question 17 Explanation:
NFA, DFA and regular expression are equal in power. So for every regular expression there exists DFA and NFA.
 Question 18
Can a DFA simulate NFA?
 A No B Yes C Sometimes D Depends of NFA
Theory-of-Computation       Finite-Automata
Question 18 Explanation:
DFA has equal power as NFA.
 Question 19
Let a and b be the regular expressions, then (a*∪b*)* is not equivalent to
 A (a∪b)* B (b*∪a*)* C (b∪a)* D (a∪b)
Theory-of-Computation       Regular-Expression
Question 19 Explanation:
The given regular expression is not equal to option D.
 Question 20
FDDI is a
 A Ring network B Star network C Mesh network D Bus based network
Computer-Networks       Topologies
Question 20 Explanation:
Fiber Distributed Data Interface (FDDI) uses fiber-optic cable and is wired in a ring topology and Fiber Distributed Data Interface (FDDI) uses token passing as its media-access method and can operate at high speeds.
 Question 21
Which one of the following is not a class of LAN?
 A Broadband B CSMA/CD C Token bus D Token ring
Computer-Networks       LAN
Question 21 Explanation:
Broadband is not a class of LAN.
 Question 22
Which of the following TCP/IP protocols is used for file transfer with minimal capability and minimal overhead?
 A RARP B FTP C TFTP D TELNET
Computer-Networks       TCP/IP
Question 22 Explanation:
Among the given options FTP and TFTP is used to transfer files. Trivial File Transfer Protocol (TFTP) is an Internet software utility for transferring files that is simpler to use than the File Transfer Protocol (FTP) but less capable. It is used where user authentication and directory visibility are not required.
 Question 23
ALOHA is used for
 A Channel allocation problem B Data transfer C Buffering D All of these
Computer-Networks       Access-Control-Methods
Question 23 Explanation:
Aloha is used to get access of the link because it is a access control method or we can also say that it is a channel allocation problem.
 Question 24
Error detection at the data link level is achieved by
 A Bit stuffing B Cyclic redundancy codes C Hamming D Equalization
Computer-Networks       CRC
Question 24 Explanation:
Error detection at the data link layer is achieved by CRC method.
There are 24 questions to complete.

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