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Unit notes and practice questions

Grade 10 Information Technology unit 2: Computer network

Everything here is for unit 2 of the Grade 10 Information Technology textbook: what the chapter covers, the short notes, practice questions with their answers, and the lesson video where one exists.

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5
Cards
10
Practice questions on unit 2
36–80
The textbook pages for unit 2

What unit 2 covers

  1. 1.Network Media (Transmission Media)
  2. 2.Telecommunications Network
  3. 3.Mobile Communications
  4. 4.Cellular Networks
  5. 5.Satellite Networks
  6. 6.Internet Protocol
  7. 7.Unit Review Exercise

Short notes for unit 2

The cards filed under this chapter on the Grade 10 Information Technology page. Open one at a time.

Transmission ModeDirection of Data FlowSimultaneous CapabilityReal-World Example
SimplexUnidirectionalNo (one-way only)Keyboard to computer, monitor
Half-DuplexBidirectionalNo (one device at a time)Walkie-talkie, one-lane road
Full-DuplexBidirectionalYes (both devices simultaneously)Telephone network, two-way street

When you use it

Use this to determine whether a communication link operates in simplex, half-duplex, or full-duplex mode.

Watch out

In half-duplex mode, transmission is two-way but never at the same time. Only full-duplex allows simultaneous two-way transmission.

Drafted from Grade 10 Information Communication Technology, pages 36-80, then checked twice before it went up

When you use it

Use when selecting the proper RJ45 twisted-pair wiring type to connect network devices.

Watch out

Straight-through connects different network devices (computer to hub or switch). Crossover cable connects similar network devices (computer to computer).

Drafted from Grade 10 Information Communication Technology, pages 36-80, then checked twice before it went up

ClassHigh Order BitsFirst Octet RangeDefault Mask
Class A00 - 127255.0.0.0
Class B10128 - 191255.255.0.0
Class C110192 - 223255.255.255.0
Class D1110224 - 239Multicast
Class E1111240 - 255Experimental

When you use it

Use this to identify the class, network mask, or address purpose of a given IPv4 address from its first octet.

Watch out

Class D and Class E do not have default subnet masks or host addresses because Class D is for multicasting and Class E is for experimental purposes.

Drafted from Grade 10 Information Communication Technology, pages 36-80, then checked twice before it went up

MediumSignal FormCommon ConnectorDirectionality
Twisted-Pair (UTP/STP)Electrical pulsesRJ45Guided
Coaxial CableElectrical signalsBNCGuided
Fiber-Optic CableLight pulsesSC, ST, MT-RJGuided
Radio WavesElectromagneticOmnidirectional antennaOmnidirectional
MicrowavesElectromagneticParabolic dish, HornUnidirectional

When you use it

Use this to match transmission media with their physical signal types, connectors, and propagation properties.

Watch out

Fiber-optic cables guide light pulses rather than electric current, which completely eliminates electrical interference.

Drafted from Grade 10 Information Communication Technology, pages 36-80, then checked twice before it went up

Orbit CategoryAltitudePosition Relative to Van Allen Belts
LEO (Low Earth Orbit)<2000 km< 2000\text{ km}Below lower Van Allen belt
MEO (Medium Earth Orbit)5000 km−15000 km5000\text{ km} - 15000\text{ km}Between the two Van Allen belts
GEO (Geostationary Earth Orbit)35786 km35786\text{ km}Single orbit above the equator

When you use it

Use this to classify artificial satellites by their altitude and relationship to the Van Allen radiation belts.

Watch out

GEO has only one specific orbit at an altitude of exactly 35,786 km, unlike LEO and MEO which span broad altitude ranges.

Drafted from Grade 10 Information Communication Technology, pages 36-80, then checked twice before it went up

Practice questions on unit 2

10 multiple-choice questions written against this chapter, each with its answer and the reason. Try one before you open the answer.

Question 1

Which connector is most commonly used to terminate unshielded twisted-pair (UTP) network cables?

  1. A.BNC connector
  2. B.RJ45 connector
  3. C.ST connector
  4. D.SC connector
Show the answer and why

Answer: B RJ45 connector

Why

RJ45 (Registered Jack 45) is the standard keyed connector used with UTP cabling to connect computers, switches, and routers.

Question 2

In a school computer lab in Hawassa, a student uses a keyboard to type data into a desktop computer. What type of data transmission mode does this represent?

  1. A.Simplex
  2. B.Half-duplex
  3. C.Full-duplex
  4. D.Duplex
Show the answer and why

Answer: A Simplex

Why

In simplex mode, communication is unidirectional (one-way). Keyboards can only send input and traditional monitors can only receive output.

Question 3

Bluetooth radio frequency transceivers operate in the unlicensed Industrial, Scientific, and Medical (ISM) band centered at which frequency?

  1. A.900 MHz
  2. B.100 MHz
  3. C.2.4 GHz
  4. D.5.8 GHz
Show the answer and why

Answer: C 2.4 GHz

Why

Bluetooth uses the unlicensed ISM frequency band centered at 2.4 gigahertz (GHz) to connect devices over short distances.

Question 4

What is the default network mask for a Class B IPv4 address?

  1. A.255.0.0.0
  2. B.255.255.0.0
  3. C.255.255.255.0
  4. D.255.255.255.255
Show the answer and why

Answer: B 255.255.0.0

Why

The default subnet mask for Class B is 255.255.0.0 because the first two octets represent the network portion.

Question 5

A student in Addis Ababa wants to connect two computers directly together without using a switch or hub. Which cable wiring should the student use?

  1. A.Ethernet straight-through cable
  2. B.Thick coaxial cable
  3. C.Single-mode fiber cable
  4. D.Ethernet crossover cable
Show the answer and why

Answer: D Ethernet crossover cable

Why

An Ethernet crossover cable is used to connect two similar devices directly together, such as computer to computer.

Question 6

In wireless transmission, what type of wave propagation occurs when high-frequency radio waves radiate upward into the ionosphere and are reflected back to Earth?

  1. A.Ground propagation
  2. B.Sky propagation
  3. C.Line-of-sight propagation
  4. D.Surface propagation
Show the answer and why

Answer: B Sky propagation

Why

In sky propagation, radio waves radiate up into the ionosphere where they are reflected back to Earth, allowing long-distance transmission with lower power.

Question 7

In a cellular network, which switching office coordinates communication between all base stations, telephone central offices, and handles billing?

  1. A.Mobile Switching Center (MSC)
  2. B.Access Point (AP)
  3. C.Base Station (BS)
  4. D.Satellite Transponder
Show the answer and why

Answer: A Mobile Switching Center (MSC)

Why

The Mobile Switching Center (MSC) is the computerized center that controls base stations, connects calls, records call information, and manages billing.

Question 8

Which fiber-optic cable connector uses a bayonet locking system and is commonly used for connecting cables to networking devices?

  1. A.Subscriber channel (SC)
  2. B.Mechanical Transfer Registered Jack (MT-RJ)
  3. C.Straight-tip (ST)
  4. D.Bayonet Neill-Concelman (BNC)
Show the answer and why

Answer: C Straight-tip (ST)

Why

The straight-tip (ST) connector uses a bayonet locking system to attach fiber-optic cables to networking devices reliably.

Question 9

How does thin coaxial cable differ from thick coaxial cable in physical size and signal transmission?

  1. A.Thin coaxial cable is approximately 4 mm in diameter and typically carries baseband signals.
  2. B.Thin coaxial cable has a diameter between 6 and 18 mm and carries broadband signals.
  3. C.Thin coaxial cable provides superior noise isolation compared to thick coaxial cable.
  4. D.Thin coaxial cable carries signals entirely as light pulses.
Show the answer and why

Answer: A Thin coaxial cable is approximately 4 mm in diameter and typically carries baseband signals.

Why

Thin coaxial cable is about 4 mm in diameter and typically carries baseband signals, whereas thick coaxial cable is 6 to 18 mm in diameter and carries broadband signals with better noise immunity.

Question 10

What is the exact orbital altitude above the surface of the Earth for a geostationary Earth orbit (GEO) satellite?

  1. A.Below 2,000 km
  2. B.Between 5,000 and 15,000 km
  3. C.35,786 km
  4. D.45,000 km
Show the answer and why

Answer: C 35,786 km

Why

A GEO satellite has only one orbit at an altitude of exactly 35,786 km above the surface of the Earth.

The app holds 12 questions on this unit, marked as you go. These are the first 10.

The textbook pages for unit 2

Unit 2 runs from page 36 to page 80 of the Ministry of Education edition.

Ministry of Education edition, English, 234 pages

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All Grade 10 Information Technology short notes

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