Which two of the following are means in which radiated interference primarily enters electronic devices? (Select two options.)

Question

Options

• AProximity to interfering sources
• BMissing or inadequate optical connections
• CMissing or inadequate device or cable shielding
• DInterface designs
• EInput signal lines

• A
  76% (19)
• B
  4% (1)
• D
  4% (1)
• E
  16% (4)

Explanation

Radiated interference enters electronic devices primarily through physical closeness to the source (A) and through gaps in shielding (C). Proximity matters because radiated electromagnetic fields weaken with distance - the nearer a device is to an interfering source, the stronger the field it is exposed to. Missing or inadequate shielding on devices or cables allows those fields to penetrate enclosures and induce unwanted currents, making it the main structural vulnerability.

Option B is wrong because optical connections use light, not electrical signals, making them inherently immune to electromagnetic interference - not a pathway for it. Option D, interface designs, relates to signal integrity and conducted emissions rather than how radiated energy enters a device. Option E, input signal lines, describes a pathway for conducted interference (noise traveling along a wire), not radiated interference entering the device itself.

Memory tip: Think "R-A-S" - Radiated interference depends on Adjacency (proximity) and Shielding (or the lack of it). If you can keep distance or wrap it in metal, you block radiated EMI.

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