WGU D413 – Telecommunications & Wireless Communications Objective Assessment | OA V1 and V2 | Questions and Answers | 2026 Update | 100% Correct.

WGU D413 – Telecommunications &
Wireless Communications Objective
Assessment | OA V1 and V2 | Questions and
Answers | 2026 Update | 100% Correct.

Domain 1: Network Fundamentals & The OSI Model
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1. A network administrator is troubleshooting a connectivity issue where data is being tran
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smitted but is corrupted due to a physical layer problem. At which layer of the OSI model d
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oes the physical cabling and signaling reside?
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A) Layer 1
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B) Layer 2
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C) Layer 3
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D) Layer 4
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Correct Answer: A) Layer 1
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2. Which OSI layer is responsible for logical addressing (IP addresses) and routing packets
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between different networks? jh jh




A) Data Link Layer
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B) Network Layer
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C) Transport Layer
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D) Session Layer
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Correct Answer: B) Network Layer
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3. Ethernet operates primarily at which two layers of the OSI model?
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A) Physical and Network
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B) Data Link and Network
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C) Physical and Data Link
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D) Transport and Session
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Correct Answer: C) Physical and Data Link
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4. A switch learns the MAC addresses of connected devices to forward frames. This functio
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n is associated with which sublayer of the Data Link Layer?
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,A) LLC (Logical Link Control)
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B) MAC (Media Access Control)
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C) Physical Coding Sublayer
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D) Network Interface Sublayer
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Correct Answer: B) MAC (Media Access Control)
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Domain 2: RF Principles & Antennas
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5. What is the fundamental relationship between wavelength and frequency in wireless co
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mmunications?
A) They are directly proportional; as frequency increases, wavelength increases.
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B) They are inversely proportional; as frequency increases, wavelength decreases.
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C) They are independent of each other.
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D) Wavelength equals frequency multiplied by the speed of light.
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Correct Answer: B) They are inversely proportional; as frequency increases, wavelength decreases
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.



6. Which antenna type radiates signal equally in all directions (horizontally) and is typically
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used for indoor Wi-Fi coverage?
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A) Yagi-Uda
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B) Parabolic Dish
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C) Omnidirectional
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D) Patch Antenna
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Correct Answer: C) Omnidirectional
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7. The loss of signal strength over distance is referred to as:
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A) Fading
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B) Absorption
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C) Path Loss (Free Space Path Loss)
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D) Reflection
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Correct Answer: C) Path Loss (Free Space Path Loss)
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8. What is the primary cause of "multipath interference" in wireless signals?
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A) Signal absorption by atmospheric gases.
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B) The signal takes different paths to the receiver, arriving at slightly different times.
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, C) The receiver is too close to the transmitter.
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D) The frequency is too low.
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Correct Answer: B) The signal takes different paths to the receiver, arriving at slightly different ti
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mes.



9. What does the term "dBm" represent in wireless networking?
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A) A ratio of signal-to-noise.
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B) A measure of absolute power relative to 1 milliwatt.
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C) A measure of antenna gain.
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D) A measure of voltage standing wave ratio.
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Correct Answer: B) A measure of absolute power relative to 1 milliwatt.
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Domain 3: Modulation & Signal Encoding jh jh jh jh jh




10. Which digital modulation technique varies the frequency of the carrier signal to represe
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nt digital data (0s and 1s)?
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A) ASK (Amplitude Shift Keying)
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B) FSK (Frequency Shift Keying)
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C) PSK (Phase Shift Keying)
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D) QAM (Quadrature Amplitude Modulation)
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Correct Answer: B) FSK (Frequency Shift Keying)
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11. QAM (Quadrature Amplitude Modulation) combines which two modulation techniques
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to achieve higher data rates?
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A) FSK and PSK
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B) ASK and PSK
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C) ASK and FSK
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D) PAM and PWM
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Correct Answer: B) ASK and PSK jh jh jh jh jh




12. What is the primary benefit of using OFDM (Orthogonal Frequency Division Multiplexin
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g) in Wi-Fi and 4G/5G?
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A) It uses a single carrier frequency for all users.
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B) It is highly resistant to multipath interference by using many sub-carriers.
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