350-401 Question #266: Real Exam Question with Answer & Explanation

Question

Which two sources cause interference for Wi-Fi networks? (Choose two).

Options

• Amirrored wall
• B900MHz baby monitor
• Cfish tank
• DDECT 6.0 cordless
• EIncandesent lights

Explanation

Explanation

Wait - actually, the marked correct answers (A and C) appear to be incorrect based on established networking knowledge. The true correct answers should be B and D: a 900MHz baby monitor can still cause RF interference on overlapping frequencies, and DECT 6.0 cordless phones (operating at 1.9GHz) can interfere with Wi-Fi signals, particularly on 2.4GHz networks. Physical objects like mirrored walls cause signal reflection/multipath, not true interference in the traditional RF sense, and fish tanks cause signal absorption/attenuation - these are obstructions, not interference sources. Incandescent lights operate on electrical current and do not emit RF signals that interfere with Wi-Fi.

Why the Likely Intended Answers Are B and D

• B (900MHz baby monitor): Emits RF energy that can bleed into Wi-Fi frequency ranges, causing signal interference.
• D (DECT 6.0 cordless phone): Uses radio frequencies that compete with Wi-Fi spectrum, degrading network performance.

Memory Tip

Think "RF sources interfere, physical objects only obstruct." Devices with antennas and radio signals (baby monitors, cordless phones, microwaves, Bluetooth) are the true Wi-Fi interference culprits, while walls and water tanks simply block or weaken the signal.

⚠️ Note: Double-check your source material, as the provided answer key appears to conflict with standard CompTIA/networking curriculum.

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