Shielded wire is used in some systems to eliminate or prevent what type of interference?

• A. Acoustic Interference
• B. Electromagnetic Interference
• C. Thermal Interference
• D. Mechanical Interference

Answer: (B)

The main idea here is reducing electromagnetic interference. Shielded wire adds a conductive layer around the conductor that acts as a Faraday shield, blocking external electromagnetic fields from reaching the signal inside and providing a low-impedance path for noise currents to ground. This keeps signals cleaner and also reduces the wire’s own emissions that could affect other circuitry. In aircraft systems, EMI can come from radios, engines, or other equipment, so shielding is a key way to protect sensitive electronics.

Acoustic, thermal, and mechanical interference involve sound waves, temperature changes, or vibrations, respectively. Shielding a wire won’t address those issues, so they’re not what shielded wire is designed to combat.