Among the following obstacles, which of the following has the largest loss of wireless signals?

Question

Options

• AGypsum ceiling
• Bglass
• C120mm brick wall
• D200mm concrete wall

• A
  17% (3)
• B
  6% (1)
• C
  6% (1)
• D
  72% (13)

Explanation

A 200mm concrete wall causes the greatest wireless signal loss because concrete is an extremely dense material, and at 200mm thickness, it presents a massive barrier to radio waves - typical attenuation can exceed 10–15 dB, effectively blocking most Wi-Fi signals. A 120mm brick wall (C) also causes significant loss, but brick is less dense than concrete, and the thinner profile means less total material for signals to penetrate, so it attenuates less than the concrete option. Glass (B) is largely transparent to radio waves with minimal signal loss, while gypsum ceilings (A) are among the most permeable common building materials, causing very little attenuation.

Memory tip: Think "denser + thicker = worse" - rank materials by density (concrete > brick > glass > gypsum) and always factor in thickness; the heaviest, thickest barrier always wins for maximum signal loss on exam questions.

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