» Wireless Fundamentals 3

By | September 24, 2012

Ensurepass
Here you will answers to Wireless Fundamentals – Part 3


Question 1

What unit of measurement is used to represent the strength of an antenna’s radiation pattern?

A. dBi
B. dBm
C. mW
D. GHz


Answer: A

Explanation

+ dBi is a unit of sound that measures acoustical and electrical power. In particular, dBi is a measure of the increase in signal (gain) by your antenna compared to the hypothetical isotropic antenna (which uniformly distributes energy in all directions) -> It is a ratio. The greater the dBi value, the higher the gain and the more acute the angle of coverage.

+ dBm is a measure of signal power. It is the the power ratio in decibel (dB) of the measured power referenced to one milliwatt (mW). The “m” stands for “milliwatt”.

Question 2

What are the four types of wireless networks? (Choose four)

A. Wireless PAN
B. LAN
C. MAN
D. VLAN
E. WAN


Answer: A B C E

Question 3

What is the typical maximum range of a wireless PAN?

A. 45 feet
B. 50 feet
C. 55 feet
D. 60 feet


Answer: B

Explanation

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Question 4

What is the general maximum coverage area of a wireless PAN?

A. within 30 feet
B. within 35 feet
C. within 40 feet
D. within 45 feet


Answer: A

Explanation

It is weird that Cisco thinks “maximum coverage area” is different from “maximum range”!  But this question has correct answer of 30 feet.

Question 5

What relatively new standard applies to wireless MANs?

A. IEEE 802.11
B. IEEE802.3Z
C. Wi-Fi
D. IEEE 802.16


Answer: D

Question 6

True or false: A computer device stores data in analog form.

A. true
B. false


Answer: B

Question 7

On what layers of the OSI reference model do wireless networks operate? (Choose two)

A. Physical layer
B. Network layer
C. data link layer
D. session layer


Answer: A C

Question 8

RF signals offer relatively short range as compared to light signals. True or false?

A. True
B. False


Answer: B

Explanation

First we need to explain about Line-of-sight & non-line-of-sight:

Line-of-sight (LOS) is a condition where a signal travels over the air directly from a wireless transmitter to a wireless receiver without passing an obstruction.

Conversely, non-line-of-sight (NLOS) is a condition where a signal from a wireless transmitter passes several obstructions before arriving at a wireless receiver. The signal may be reflected, refracted, diffracted, absorbed or scattered.

In most case RF signals are line-of-sight signal and “light” is a non-line-of-sight signal so FR signals offer longer range than light signals.

Question 9

Spread spectrum generally requires user licenses. True or false?

A. True
B. False


Answer: B

Explanation

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Question 10

Approximately up to what range do direct infrared systems operate?

A. 0.5 mile
B. 1 mile
C. 1.5 mile
D. 2.0 mile


Answer: B

Explanation

The range of an infrared light system can vary from a few feet with PDA applications to 1 mile with direct infrared systems. This is significantly less range than with RF systems.