Download 1 - A1.net

1
What is the term for signal loss due to a light pulse hitting particles and scattering the light?
reflection
dispersion
absorption
refraction
2 Which statements are true of alternating current? (Select three.)
The magnetic field continually collapses and rebuilds.
It is the type of electricity available from the power mains in most countries.
It is produced by batteries.
Magnetic lines of force occur in one orientation.
It can cause interference in nearby structured wiring cables.
Current flows in one direction.
3 What is IP Telephony?
connecting to the Internet over a telephone line
connecting to a LAN over a telephone line
using the IP protocol on a telephone system
using the Internet as a telephone system
4 What happens when a sufficient amount of current is sensed on the ground wire of a GFCI device?
the flow of electrons is stopped
the main circuit breaker panel is tripped
a red warning light is activated on the GFCI device
an amber warning light is activated on the GFCI device
5 What is the maximum length of a cable segment using 10BASE-T?
100 meters
185 meters
200 meters
500 meters
6 What is the resistance value, if voltage=12 volts and current=3 amps?
36 ohms
4 ohms
0.75 ohms
2 ohms
7 When two conductors are close together but are separated by some kind of insulator, the movement of charges on one of the
conductors can cause corresponding movement of charges on the other. What is this effect called?
inductance
resistance
voltage
capacitance
8 How many twisted pairs does 100BASE-TX (Fast Ethernet) use?
1 pair
2 pairs
3 pairs
4 pairs
9 What is used in multi-floor buildings to equalize any differences between the ground circuits at different points in the structure?
grounding equalizer
bonding cable
grid balancer
electrical riser
10 Which method of signal transmission uses radio waves to carry signals?
electrical
optical
wireless
acoustic
11 How can AC power line noise be minimized?
periodically unplug all network devices
ensure a good ground connection
use anti-static devices
lengthen electrical lines within walls
12 Which topology does a FDDI network use?
dual ring
bus
star
extended star
13 What is the unit of measurement for current?
ampere
ohm
watt
volt
14 Which characteristic of a cable is affected by improper handling or terminating?
current
voltage
power
impedance
15 When does electrostatic discharge occur?
when electrons that have been at rest suddenly jump to a conductor
when the current in a wire changes direction
when a grounding strap is used
when there is an excessive amount of inductance
16
What is the result when too much wire is untwisted when the connector is attached to the wire?
there is no effect
far-end crosstalk
near-end crosstalk
middle crosstalk
17 What is the unit of measurement for resistance?
ampere
ohm
watt
volt
18 Which standard is used by most large cable companies for sending data over cable television cables?
DOCSIS
CATV
HFC
MCNS
19 Which statements are true of digital signals? (Select two.)
They must be transmitted in real time.
Their voltage varies continuously.
They are extremely versatile.
They are not as robust as analog signals.
They contain patterns of ones and zeros.
20 Which of the following are characteristics of ISDN? (Select three.)
both digital and analog
communicates easily with most networks
transmits data over a single channel
uses existing telephone lines
cannot transmit voice
faster call setup than a modem
21 How much current does a 110 volt, 1100 watt microwave oven draw?
0.1 amps
10 amps
1100 amps
121,000 amps
22 What is meant by asymmetrical DSL?
Its two frequencies are not used evenly.
It is used more often for voice than for data.
Throughput is better at certain times of day than at others.
More bandwidth is allocated for downloads than uploads.
23 Which device is used to reduce the high voltages of power lines to 120 and 240 volts?
rectifier
inductor
transformer
power supply
24 What is one function of a modem?
to convert analog signals to digital signals before sending them over a phone line
to convert digital signals to analog signals after receiving them over a phone line
to convert digital signals to analog signals before sending them over a phone line
all of the above
25 What causes attenuation in a copper wire?
acoustic vibrations
external light sources
resistance in the wire
polyurethane coating on the wires
26 The input to a device measures 2mW of power. If the device produces a 3dB gain, how much power is on the output of the de
3 mW
4 mW
5 mW
6 mW
27 Which factors can cause signal loss in a fiber optic cable? (Select two.)
electromagnetic interference
crosstalk
small particles trapped inside the glass
misaligned connectors
28 What is the term for the bi-directional flow of electrically charged carriers?
alternating current
direct current
propagation delay
delay skew
29 The common wall outlet is an example of what type of electricity?
alternating current
short circuit
open circuit
direct current
30 What is the unit of measurement for attenuation?
amps
volts
ohms
decibels
31
What is the movement of electrons called?
voltage
current
resistance
power
32 Which property describes the forming of fields around a wire?
inductance
resistance
voltage
capacitance
33 Which statement is true of a varying DC signal?
It is the same as an AC signal.
It varies between zero volts and some higher value.
It is more efficient than a modulated DC signal.
It turns the signal off and on to transmit.