Security & Physical Layer (Multiplexing, Physical Media) Interview/Exam Question-Answer

Q.1 The sharing of a medium and its link by two or more devices is called _________.

       A. Fully duplexing

       B. Multiplexing

       C. Micropleixng

       D. Duplexing

Ans : Multiplexing

Q.2 Multiplexing is used in _______.

       A. Packet switching

       B. Circuit switching

       C. Data switching

       D. Packet & Circuit switching

Ans : Circuit switching

Q.3 Which multiplexing technique used to transmit digital signals?

       A. FDM

       B. TDM

       C. WDM

       D. FDM & WDM

Ans : TDM

Q.4 If there are n signal sources of same data rate, then the TDM link has _______ slots.

       A. n

       B. n/2

       C. n*2

       D. 2n

Ans : n

Q.5 If link transmits 4000 frames per second, and each slot has 8 bits, the transmission rate of circuit this TDM is _________.

       A. 32kbps

       B. 500bps

       C. 500bps

       D. 32bps

Ans : 32kbps

Frame rate = 4000/sec and number of bits in slot = 8

Transmission rate = (4000 * 8) bps
= 32000bps
= 32kbps

Q.6 The state when dedicated signals are idle are called __________.

       A. Death period

       B. Poison period

       C. Silent period

       D. Stop period

Ans : Silent period

Q.7 Multiplexing provides _________.

       A. Efficiency

       B. Privacy

       C. Anti jamming

       D. Both Efficiency & Privacy

Ans : Both Efficiency & Privacy

Q.8 In TDM, the transmission rate of a multiplexed path is always _______ the sum of the transmission rates of the signal sources.

       A. Greater than

       B. Lesser than

       C. Equal to

       D. Equal to or greater than

Ans : Greater than

Q.9 In TDM, slots are further divided into _________.

       A. Seconds

       B. Frames

       C. Packets

       D. Bits

Ans : Frames

Q.10 Which of this is not a guided media?

       A. Fiber optical cable

       B. Coaxial cable

       C. Wireless LAN

       D. Copper wire

Ans : Wireless LAN

Q.11 UTP is commonly used in __________.

       A. DSL

       B. FTTP

       C. HTTP

       D. None of the above

Ans : DSL

Q.12 Coaxial cable consists of _______ concentric copper conductors.

       A. 1

       B. 2

       C. 3

       D. 4

Ans : 2

Q.13 Fiber optics posses following properties __________.

       A. Immune electromagnetic interference

       B. Very less signal attenuation

       C. Very hard to tap

       D. All of the above

Ans : All of the above

Q.14 If an Optical Carrier is represented as OC-n, generally the link speed equals(in Mbps) __________.

       A. n*39.8

       B. n*51.8

       C. 2n*51.8

       D. None of the above

Ans : n*51.8

Q.15 Terrestrial radio channels are broadly classifed into _____ groups.

       A. 1

       B. 2

       C. 3

       D. 4

Ans : 3

Q.16 Radio channels are attractive medium because __________

       A. Can penetrate walls

       B. Connectivity can be given to mobile user

       C. Can carry signals for long distance

       D. All of the above

Ans : All of the above

Q.17 Geostationary satellites ___________.

       A. Are placed at a fixed point above the earth

       B. Rotate the earth about a fixed axis

       C. Rotate the earth about a varying axis

       D. All of the above

Ans : Are placed at a fixed point above the earth

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