CCNA1 Module 3 practice test

1 Electrons move away from the negative terminal of a battery and round a circuit because:

• electrons are neutral and cannot be held by atoms so they have to keep moving
• the negative charge on the electron is repelled by the negative charge on the terminal
• the negative charge on the electron is attracted by the negative charge on the terminal
• the positive charge on the electron is repelled by the negative charge on the terminal

2 Which are true? (Choose two)

• An electrical current needs to flow in a closed loop, so copper data cables must provide a wire for sending signals and also a return path.
• An electrical current needs a source of voltage, a loop of insulating material and a switch.
• Copper is used for data cables because it is a good conductor of electricity, it resists corrosion and it can be drawn out into thin wires.
• The human body is a good electrical insulator.
• Mains electricity provides a DC voltage whereas a battery provides an AC voltage.

3 Which of the following are advantages of UTP cable over STP cable for LAN networking? (Choose three)

• UTP cable is easier to install than STP cable
• UTP cable gives less electrical interference than STP cable
• UTP cable allows a longer length of cabling than STP cable
• UTP cable is cheaper than STP cable
• UTP cable does not need to be grounded (earthed) at each end but STP cable does

4 Which of the following correctly describes the type of signal that the network media carries?

• Coaxial cable carries pulses of light
• UTP cable carries impedence signals
• STP cable carries electrical impulses
• Fiber-optic cable carries electrical impulses

5 Which of the following are true about impedence in network cabling? (Choose two)

• Impedence involves resistance and reactance to current caused by signal degradation
• Electrical components in the NIC create impedence on the networking media
• Impedence is made up of resistance, capacitance and inductance effects
• Networking media impedence needs to match the network interface card electrical components otherwise the signal will be degraded

6 Which network medium carries pulses of light?

• Coaxial cable
• Fibre-optic cable
• UTP cable
• STP cable

7 What is the cause of crosstalk in a cable?

• Cable wires that are too large in diameter
• Too much noise in a cable’s data signal
• Electrical motors and lighting
• Electrical signals from other wires in a cable

8 Which of the following best describes attenuation?

• The termination of a message
• The interception of a message
• The weakening of a message
• The ignoring of a message

9 Which of the following are true about coaxial cable? (Choose three)

• It is recommended as the best type of cabling for LANs
• It is no longer recommended for cabling LANs
• It includes shielding that is also used as a return path for signals
• It provides higher bandwidth than fibre optic cables
• It is easier to install than UTP cable
• It requires fewer repeaters than UTP cabling because cables can be longer

10 What is category 5 UTP cabling suitable for?

• Transmitting data at speeds up to 10 Mbps
• Transmitting data at speeds up to 100 Mbps
• It is only suitable for phone lines
• It is used mainly for Token Ring networks

11 If a network is described as 10BASE-T Ethernet, what does this tell you about the cabling?

• Coaxial cable using baseband signalling and transmitting data at 10 Mbps
• Twisted pair cable using baseband signalling and transmitting data at 10 Mbps
• Fibre optic cable using baseband signalling and transmitting data at 10 Gbps
• Twisted pair cable using broadband signalling and transmitting data at 10 Mbps

12 What does the specification 10BASE5 tell you about a cable? (Choose three)

• the type of transmission to be used
• the maximum length of cable to be used
• the number of hosts allowed on one cable
• the intended bandwidth in Mbps
• the number of repeaters or hubs to be used
• the protocol for encoding bits into electrical signals

13 A ray of light changes direction (bends) as it passes the boundary from one transparent material to another. Which of the following are true? (Choose three)

The amount of bending depends on the indexes of refraction of the two materials

Total internal reflection occurs when all the light passes from one material into the other material

The speed of the light does not change when it passes from one material to the other

The speed of the light increases when it passes into a material of lower optical density (lower index of refraction)

Glass has a lower index of refraction (lower optical density) than air

The speed of light is greatest in a vacuum, but its speed in air is not much less.

14 A fibre optic cable is described as 9/125 micron cable. Which of the following are true? (Choose two)

• The cable is a multimode cable
• The cable is a single mode cable
• The core is 9 mm and the complete cable is 125 mm in diameter
• The core is 9 mm and the cladding is 125 mm in diameter
• The cladding is 9 mm and the core is 125 mm in diameter

15 Which of the following are true about single mode and multimode fibre optic cable? (Choose three)

• Multimode cable provides a higher bandwidth than single mode.
• Single mode cable can be used over longer distances than multimode cable.
• Single mode cable has a narrower core than multimode cable.
• Single mode cable uses a LED as a light source
• Single mode cable uses an infra red laser as a light source
• Multimode cable has a single light path

16 Which are true for fibre optic cables? (Choose three)

• Electrical interference from motors can cause noise in fibre optic cables
• Microwave ovens and wireless phones can cause noise in fibre optic cables
• Light absorption in fibre optic cables can lead to loss of signal strength
• Scattering of light in fibre optic cables can lead to loss of signal strength
• Crosstalk can be a problem with fibre optic cables
• Splicing of cables with different core sizes can lead to loss of signal strength

17 When a light signal enters a fibre optic cable, its angle of incidence must be greater than the critical angle for the core and cladding. Why is this?

• Total internal reflection will occur and keep the light inside the core
• Total internal reflection will occur and allow light to enter the cladding
• It is necessary to avoid total internal reflection because it generates noise
• It is necessary to avoid total internal reflection and attenuation of signals

18 Which of these statements about PIN photodiodes are true? (Choose two)

• They provide a source of light for multimode optical fibre cables
• They provide a source of light for single mode optical fibre cables
• They act as receiving devices for light of all wavelengths
• They act as receiving devices for light of a specific wavelength
• They convert light signals to electrical pulses
• They convert electrical pulses to light signals

19 What is an optical link loss budget?

• The money set aside for repairs to optical fibre cable systems
• The measured signal attenuation over a fibre optic link
• The attenuation of a signal caused by faulty connectors linking optical fibre cables
• The calculated power loss that can be tolerated over a fibre optic link

20 Why are two fibres required in a fibre optic cable connection?

• To provide full duplex transmission so that signals can travel in both directions at the same time
• To provide a back up in case of damage to the first fibre
• To send two copies of every message so that the versions can be compared at the receiving end
• To provide half duplex transmission with rapid switching from one direction to the other

21 Which statements about optical fibre cables are true? (Choose three)

· It is dangerous to look into live fibre optic cables or transmitters because laser light can damage your eyes even though it is a wavelength that you cannot see.

· Laser light is so powerful that loss of light in fibre optic cables and connectors is not an issue.

· It is important to keep fibre optic cable ends and connectors clean because dirt and dust can cause serious loss of light which results in signal attenuation.

· Optical fibre cable is cheaper and easier to install than copper UTP cable.

· Optical cable ends must be cleaved and polished then inspected before fitting connectors. This ensures that the ends are properly smooth and shaped.

22 Wireless networks operating to the 802.11b standard are sometimes known as Wi-Fi. At what data rates are they able to operate according to the standard?

• 1 and 2 Mbps
• 5.5 and 11 Mbps
• 1, 2, 5.5 and 11 Mbps
• 20 to 40 Mbps

23 Why is the actual throughput for sending messages on a wireless network at most only 50% (half) of the data rate specified?

• The data rate is halved to reduce interference from electrical equipment.
• Every time a device sends a signal, the receiving device sends an acknowledgement and these acknowledgements use up half of the bandwidth.
• Each signal is sent twice so that it can be authenticated on receipt.
• Devices need to be compatible with devices from earlier standards where the data rate was half as fast.

24 Why is it desirable to have a 20% to 30% overlap in the areas served by wireless network access points?

• It allows equipment to be moved around while maintaining contact with the wireless network.
• The double signal in the overlapping area allows rates of transmission to be higher.
• It minimises disruption when equipment is faulty.
• It allows greater security because unauthorised devices will not be able to connect to the network.

25 Which of the following are likely to cause interference on a wireless network? (Choose three)

• Bluetooth devices operating in the 2.4 GHz range of wavelengths
• Leakage of radiation from microwave ovens
• Infra red remote controls for TVs and videos
• Radio receivers tuned to FM stations
• Wireless phones operating at 2.4 GHz