# » 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

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

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

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

Question 6

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

A. true
B. false

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

Question 8

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

A. True
B. False

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

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