UGC-NET CS 2017 Nov - III

Question 21

Pumping lemma for regular language is generally used for proving:

• whether two given regular expressions are equivalent
• a given grammar is ambiguous
• a given grammar is regular
• a given grammar is not regular

Question 22

Which of the following problems is undecidable?

• To determine if two finite automata are equivalent
• Membership problem for context free grammar
• Finiteness problem for finite automata
• Ambiguity problem for context free grammar

Question 23

Finite state machine can recognize language generated by __________.

• Only context free grammar
• Only context sensitive grammar
• Only regular grammar
• any unambiguous grammar

Question 24

The language L = {aⁱb cⁱ │ i >= 0} over the alphabet {a, b, c} is:

• a regular language.

• not a deterministic context free language but a context free language.

• recursive and is a deterministic context free language.

• not recursive.

Question 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?

• 192 kbps
• 512 kbps
• 1.248 Mbps
• 1.536 Mbps

Question 26

Quadrature Amplitude Modulation means changing both:

• Frequency and phase of the carrier.
• Frequency and Amplitude of the carrier.
• Amplitude and phase of the carrier.
• Amplitude and Wavelength of the carrier.

Question 27

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

• 1 kbps
• 1.25 kbps
• 2 kbps
• 10 kbps

Question 28

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?

• 62 subnets and 1022 hosts
• 64 subnets and 1024 hosts
• 62 subnets and 254 hosts
• 64 subnets and 256 hosts

Question 29

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.

• (a) and (b) Only
• (b) and (c) Only
• (a) and (c) Only
• (a), (b) and (c)

Question 30

Consider a full binary tree with n internal nodes, internal path length i, and external path length e. The internal path length of a full binary tree is the sum, taken over all nodes of the tree, of the depth of each node. Similarly, the external path length is the sum, taken over all leaves of the tree, of the depth of each leaf. Which of the following is correct for the full binary tree?

• e = i+n
• e = i+2n
• e = 2i+n
• e = 2ⁿ+i