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

## Monday, 26 September 2016

21.       Assume that the program ‘P’ is implementing parameter passing with ‘call by reference’. What will be printed by following print statements in P?
Program P()
{
x = 10;
y = 3;
funb (y, x, x)
print x;
print y;
}
funb (x, y, z)
{
y = y + 4;
z = x + y + z;
}
(A) 10, 7             (B) 31, 3
(C) 10, 3            (D) 31, 7
22.       The regular grammar for the language L = {anbm | n + m is even} is given by
(A) S → S1 | S2
S1 → a S1 | A1
A1 → b A1 | λ
S2 → aaS2 | A2
A2 → b A2 | λ
(B) S → S1 | S2
S1 → a S1 | a A1
S2 → aa S2 | A2
A1 → bA1 | λ
A2 → bA2 | λ
(C) S → S1 | S2
S1 → aaa S1 | aA1
S2 → aaS2 | A2
A1 → bA1 | λ
A2 → bA2 | λ
(D) S → S1 | S2
S1 → aa S1 | A1
S2 → aaS2 | aA2
A1 → bbA1 | λ
A2 → bbA2 | b
23.       Let Σ = {a, b} and language L = {aa, bb}. Then, the complement of L is
(A) {λ, a, b, ab, ba} È {w ϵ {a, b}* | |w| > 3}
(B) {a, b, ab, ba} È {w ϵ {a, b}* | |w| ≥ 3}
(C) {w ϵ { a, b}* | |w| > 3} È {a, b, ab, ba}
(D) {λ, a, b, ab, ba} È {w ϵ {a, b}* | |w| ≥ 3}
24.       Consider the following identities for regular expressions :
(a) (r + s)* = (s + r)*
(b) (r*)* = r*
(c) (r* s*)* = (r + s)*
Which of the above identities are true ?
(A) (a) and (b) only      (B) (b) and (c) only
(C) (c) and (a) only      (D) (a), (b) and (c)
25.       Suppose transmission rate of a channel is 32 kbps. If there are ‘8’ routes from source to destination and each packet p contains 8000 bits. Total end to end delay in sending packet P is ................
(A) 2 sec            (B) 3 sec
(C) 4 sec            (D) 1 sec

26.       Consider the following statements :
a. High speed Ethernet works on optic fiber.
b. A point to point protocol over Ethernet is a network protocol for encapsulating PPP frames inside Ethernet frames.
c. High speed Ethernet does not work on optic fiber.
d. A point to point protocol over Ethernet is a network protocol for encapsulating Ethernet frames inside PPP frames.
Which of the following is correct ?
(A) a and b are true; c and d are false.
(B) a and b are false; c and d are true.
(C) a, b, c and d are true.
(D) a, b, c and d are false.
27.       In CRC checksum method, assume that given frame for transmission is 1101011011 and the generator polynomial is G(x) = x4 + x + 1.
After implementing CRC encoder, the encoded word sent from sender side is .............
(A) 11010110111110
(B) 11101101011011
(C) 110101111100111
(D) 110101111001111
28.       A slotted ALOHA network transmits 200 bits frames using a shared channel with 200 kbps bandwidth. If the system (all stations put together) produces 1000 frames per second, then the throughput of the system is .................
(A) 0.268           (B) 0.468
(C) 0.368           (D) 0.568
29.       An analog signal has a bit rate of 8000 bps and a baud rate of 1000.
Then analog signal has .............. signal elements and carry ............ data elements in each signal.
(A) 256, 8 bits               (B) 128, 4 bits
(C) 256, 4 bits               (D) 128, 8 bits