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

## Monday, 1 August 2016

21.       Which of the following is false regarding the evaluation of computer programming languages?
(A) Application oriented features      (B) Efficiency and Readability
(C) Software development                 (D) Hardware maintenance cost
22.       The symmetric difference of two sets S1 and S2 is defined as
S1ΘS2 = {x|xϵS1 or xϵS2, but x is not in both S1 and S2}
The nor of two languages is defined as
nor (L1,L2) = {w|w L1 and w|w L2}
Which of the following is correct?
(A) The family of regular languages is closed under symmetric difference but not closed under nor.
(B) The family of regular languages is closed under nor but not closed under symmetric difference.
(C) The family of regular languages are closed under both symmetric difference and nor.
(D) The family of regular languages are not closed under both symmetric difference and nor.
23.       The regular expression for the complement of the language L = {anbm|n≥4, m≤3} is:
(A) (λ + a + aa + aaa)b* + a*bbbb* + (a + b)*ba(a + b)*
(B) (λ + a + aa + aaa)b* + a*bbbbb* + (a + b)*ab(a + b)*
(C) (λ + a + aa + aaa) + a*bbbbb* + (a + b)*ab(a + b)*
(D) (λ + a + aa + aaa)b* + a*bbbbb* + (a + b)*ba(a + b)*
24.       Consider the following two languages:
L1 = {0i1j | gcd(i,j)=1}
L2 is any subset of 0*.
Which of the following is correct?
(A) L1 is regular and L2* is not regular
(B) L1 is not regular and L2* is regular
(C) Both L1 and L2* are regular languages
(D) Both L1 and L2* are not regular languages
25.       If link transmits 4000 frames per second and each slot has 8 bits, the transmission rate of circuit of this TDM is ...............
(A) 64 Kbps       (B) 32 Mbps
(C) 32 Kbps      (D) 64 Mbps

26.       Given the following statements:
(a) Frequency Division Multiplexing is a technique that can be applied when the bandwidth of a link is greater than combined bandwidth of signals to be transmitted.
(b) Wavelength Division Multiplexing (WDM) is an analog multiplexing Technique to combine optical signals.
(c) WDM is a Digital Multiplexing Technique.
(d) TDM is a Digital Multiplexing Technique.
Which of the following is correct?
(A) (a), (b), (c) and (d) are true.
(B) (a), (b), (c) and (d) are false.
(C) (a), (b) and (d) are false; (c) is true.
(D) (a), (b) and (d) are true; (c) is false.
27.       A pure ALOHA Network transmit 200 bit frames using a shared channel with 200 Kbps bandwidth. If the system (all stations put together) produces 500 frames per second, then the throughput of the system is ..............
(A) 0.384           (B) 0.184
(C) 0.286           (D) 0.586
28.       Match the following:
(a) Line coding                         (i) A technique to change analog signal to digital data.
(b) Block coding                       (ii) Provides synchronization without increasing
number of bits
(c) Scrambling                          (iii) Process of converting digital data to digital signal.
(d) Pulse code modulation    (iv) Provides redundancy to ensure synchronization
and inherits error detection.
Codes:
(a)   (b)   (c)   (d)
(A) (iv)  (iii)   (ii)   (i)
(B) (iii)  (iv)   (ii)   (i)
(C) (i)    (iii)   (ii)   (iv)
(D) (ii)   (i)    (iv)   (iii)
29.       Assume that we need to download text documents at the rate of 100 pages per minute. A page is an average of 24 lines with 80 characters in each line and each character requires 8 bits. Then the required bit rate of the channel is ................
(A) 1.636 Kbps             (B) 1.636 Mbps
(C) 2.272 Mbps                        (D) 3.272 Kbps
Answer: Marks given to all
30.    Encrypt the plain text Message “EXTRANET” using Transposition cipher technique with the following key:
 3 5 2 1 4 (Cipher text) 1 2 3 4 5 (Plain text)
Using ‘Z’ as bogus character.
(A) TAXERTZENZ                   (B) EXTRANETZZ
(C) EZXZTRZANZET              (D) EXTZRANZETZ