WGU D413 – Telecommunications & Wireless Communications |
Practice Questions 1–150 Most Recent exam COMPLETE (2026)
EXAM Questions and Answers (Verified Answers) (Latest Update
2026)
1. Which layer of the OSI model is responsible for end-to-end
communication and reliability?
A. Transport Layer
Rationale: The transport layer (TCP/UDP) ensures data delivery and
manages error detection and flow control.
2. Which frequency band is commonly used for 5G NR (New Radio) low-
band spectrum?
C. 600–700 MHz
Rationale: Low-band 5G uses sub-1 GHz frequencies for wide coverage.
3. What is the main purpose of multiplexing in telecommunications?
B. To transmit multiple signals over a single channel
Rationale: Multiplexing increases efficiency by combining multiple signals
on one medium.
4. Which technology allows multiple users to share the same frequency
using unique codes?
D. CDMA
Rationale: Code Division Multiple Access assigns unique codes to users to
share spectrum.
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, 5. Which topology features a central hub connecting all nodes?
A. Star
Rationale: In a star topology, all devices connect to a central hub or switch.
6. What is the typical wavelength range of microwave signals used in
wireless communication?
B. 1 mm to 1 m
Rationale: Microwaves occupy the 300 MHz–300 GHz spectrum,
corresponding to these wavelengths.
7. Which modulation technique changes the amplitude of a carrier signal
according to the input?
A. AM (Amplitude Modulation)
Rationale: AM varies the carrier amplitude while keeping frequency
constant.
8. Which type of wireless network typically covers a small geographic area
like an office?
C. WLAN
Rationale: Wireless Local Area Networks (WLANs) provide coverage in
confined areas.
9. In cellular networks, what is the primary purpose of a cell tower?
D. To provide coverage and route calls/data to mobile devices
Rationale: Cell towers transmit and receive signals within a cell to connect
users.
10.Which protocol is used for secure remote access over the internet?
B. SSH
Rationale: Secure Shell (SSH) encrypts remote terminal sessions.
11.What is the main advantage of OFDM (Orthogonal Frequency-Division
Multiplexing)?
C. Reduces interference and increases spectral efficiency
Rationale: OFDM divides a channel into orthogonal subcarriers to avoid
overlap.
12.Which wireless technology is designed for very short-range
communication, often a few centimeters?
A. NFC (Near Field Communication)
Rationale: NFC enables secure communication over very short distances.
13.Which layer of the TCP/IP model corresponds to the OSI’s Network
Layer?
B. Internet Layer
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, Rationale: The Internet Layer handles logical addressing and routing in
TCP/IP.
14.What is the main purpose of a MAC address?
A. To uniquely identify a network interface
Rationale: MAC addresses are hardware identifiers for network devices.
15.Which of the following is a disadvantage of wireless communication
compared to wired?
C. More susceptible to interference
Rationale: Wireless signals can be affected by physical obstacles, weather,
and other signals.
16.In LTE, what does the term eNodeB refer to?
B. Base station
Rationale: eNodeB is the LTE base station connecting user devices to the
network.
17.Which multiple access technique is used in GSM networks?
A. TDMA
Rationale: Time Division Multiple Access divides channels into time slots
for multiple users.
18.Which of the following is a function of a router?
D. Forward packets between networks based on IP addresses
Rationale: Routers route data between different networks using layer 3
information.
19.What does latency measure in a network?
B. The time it takes for data to travel from source to destination
Rationale: Latency is the delay experienced in transmitting data across a
network.
20.Which wireless standard is known as Wi-Fi 6?
C. IEEE 802.11ax
Rationale: 802.11ax improves speed, efficiency, and capacity over previous
Wi-Fi standards.
21.Which of these is a line-of-sight communication method?
A. Microwave
Rationale: Microwaves typically require unobstructed paths between
transmitter and receiver.
22.What is the function of a gateway in telecommunications?
D. Connects two different types of networks
Rationale: Gateways translate protocols and enable communication between
3
networks.
Page
EXAMPREPMASTER
Practice Questions 1–150 Most Recent exam COMPLETE (2026)
EXAM Questions and Answers (Verified Answers) (Latest Update
2026)
1. Which layer of the OSI model is responsible for end-to-end
communication and reliability?
A. Transport Layer
Rationale: The transport layer (TCP/UDP) ensures data delivery and
manages error detection and flow control.
2. Which frequency band is commonly used for 5G NR (New Radio) low-
band spectrum?
C. 600–700 MHz
Rationale: Low-band 5G uses sub-1 GHz frequencies for wide coverage.
3. What is the main purpose of multiplexing in telecommunications?
B. To transmit multiple signals over a single channel
Rationale: Multiplexing increases efficiency by combining multiple signals
on one medium.
4. Which technology allows multiple users to share the same frequency
using unique codes?
D. CDMA
Rationale: Code Division Multiple Access assigns unique codes to users to
share spectrum.
1
Page
EXAMPREPMASTER
, 5. Which topology features a central hub connecting all nodes?
A. Star
Rationale: In a star topology, all devices connect to a central hub or switch.
6. What is the typical wavelength range of microwave signals used in
wireless communication?
B. 1 mm to 1 m
Rationale: Microwaves occupy the 300 MHz–300 GHz spectrum,
corresponding to these wavelengths.
7. Which modulation technique changes the amplitude of a carrier signal
according to the input?
A. AM (Amplitude Modulation)
Rationale: AM varies the carrier amplitude while keeping frequency
constant.
8. Which type of wireless network typically covers a small geographic area
like an office?
C. WLAN
Rationale: Wireless Local Area Networks (WLANs) provide coverage in
confined areas.
9. In cellular networks, what is the primary purpose of a cell tower?
D. To provide coverage and route calls/data to mobile devices
Rationale: Cell towers transmit and receive signals within a cell to connect
users.
10.Which protocol is used for secure remote access over the internet?
B. SSH
Rationale: Secure Shell (SSH) encrypts remote terminal sessions.
11.What is the main advantage of OFDM (Orthogonal Frequency-Division
Multiplexing)?
C. Reduces interference and increases spectral efficiency
Rationale: OFDM divides a channel into orthogonal subcarriers to avoid
overlap.
12.Which wireless technology is designed for very short-range
communication, often a few centimeters?
A. NFC (Near Field Communication)
Rationale: NFC enables secure communication over very short distances.
13.Which layer of the TCP/IP model corresponds to the OSI’s Network
Layer?
B. Internet Layer
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Page
EXAMPREPMASTER
, Rationale: The Internet Layer handles logical addressing and routing in
TCP/IP.
14.What is the main purpose of a MAC address?
A. To uniquely identify a network interface
Rationale: MAC addresses are hardware identifiers for network devices.
15.Which of the following is a disadvantage of wireless communication
compared to wired?
C. More susceptible to interference
Rationale: Wireless signals can be affected by physical obstacles, weather,
and other signals.
16.In LTE, what does the term eNodeB refer to?
B. Base station
Rationale: eNodeB is the LTE base station connecting user devices to the
network.
17.Which multiple access technique is used in GSM networks?
A. TDMA
Rationale: Time Division Multiple Access divides channels into time slots
for multiple users.
18.Which of the following is a function of a router?
D. Forward packets between networks based on IP addresses
Rationale: Routers route data between different networks using layer 3
information.
19.What does latency measure in a network?
B. The time it takes for data to travel from source to destination
Rationale: Latency is the delay experienced in transmitting data across a
network.
20.Which wireless standard is known as Wi-Fi 6?
C. IEEE 802.11ax
Rationale: 802.11ax improves speed, efficiency, and capacity over previous
Wi-Fi standards.
21.Which of these is a line-of-sight communication method?
A. Microwave
Rationale: Microwaves typically require unobstructed paths between
transmitter and receiver.
22.What is the function of a gateway in telecommunications?
D. Connects two different types of networks
Rationale: Gateways translate protocols and enable communication between
3
networks.
Page
EXAMPREPMASTER
