21.
Pumping lemma for regular language is
generally used for proving:

(1) whether
two given regular expressions are equivalent

(2) a given
grammar is ambiguous

(3) a given
grammar is regular

(4) a given
grammar is not regular

Answer: 4

22. Which
of the following problems is undecidable?

(1) To
determine if two finite automata are equivalent

(2)
Membership problem for context free grammar

(3)
Finiteness problem for finite automata

(4)
Ambiguity problem for context free grammar

Answer: 4

23. Finite
state machine can recognize language generated by ....................

(1) Only
context free grammar

(2) Only
context sensitive grammar

(3) Only
regular grammar

(4) any
unambiguous grammar

Answer: 3

24. The
language L = {a

^{i}b c^{i }| i ≥ 0} over the alphabet {a, b, c} is:
(1) a
regular language.

(2) not a
deterministic context free language but a context free language.

(3)
recursive and is a deterministic context free language.

(4) not
recursive.

Answer: 3

25. Suppose
we want to download text documents at the rate of 100 pages per second. Assume that
a page consists of an average of 24 lines with 80 characters in each line. What
is the required bit rate of the channel?

(1) 192 kbps

(2) 512 kbps

(3) 1.248
Mbps

(4) 1.536
Mbps

Answer: 4

26. Quadrature
Amplitude Modulation means changing both:

(1)
Frequency and phase of the carrier.

(2)
Frequency and Amplitude of the carrier.

(3)
Amplitude and phase of the carrier.

(4)
Amplitude and Wavelength of the carrier.

Answer: 3

27. If
a file consisting of 50,000 characters takes 40 seconds to send, then the data
rate is ........................

(1) 1 kbps

(2) 1.25
kbps

(3) 2 kbps

(4) 10 kbps

Answer: 4

28. Match
the following:

**List - I**

(a) Data
link layer

(b) Network
layer

(c)
Transport layer

(d)
Presentation layer

**List - II**

(i)
Encryption

(ii)
Connection control

(iii)
Routing

(iv) Framing

**Code :**

(a) (b) (c) (d)

(1) (iv)
(iii) (i) (ii)

(2) (iii) (iv)
(ii) (i)

(3) (iv)
(ii) (iii) (i)

(4) (iv)
(iii) (ii) (i)

Answer: 4

29. The
address of a class B host is to be split into subnets with a 6 - bit subnet
number. What is the maximum number of subnets and maximum number of hosts in
each subnet?

(1) 62
subnets and 1022 hosts

(2) 64
subnets and 1024 hosts

(3) 62
subnets and 254 hosts

(4) 64
subnets and 256 hosts

Answer: 1

30. Which
of the following statements are true?

(a) The
fragmentation fields in the base header section of IPv4 have moved to the fragmentation
extension header in IPv6.

(b) The
authentication extension header is new in IPv6.

(c) The
record route option is not implemented in IPv6.

**Code :**

(1) (a) and
(b) Only

(2) (b) and
(c) Only

(3) (a) and
(c) Only

(4) (a), (b)
and (c)

Answer: 4

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