Exam-style question
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Which of the following best describes attenuation in a transmission medium?.
- A.The increase in signal amplitude as it travels along the cable.
- B.The reduction in signal strength due to energy loss in the medium.
- C.The conversion of electrical energy into magnetic energy.
- D.The amplification of noise signals at the receiver end.
Model answer
What a good answer should say
- The reduction in signal strength due to energy loss in the medium.
Explanation
Why this works
Formula: Attenuation (dB) = 10 log10(P_in/P_out). Substitution: P_in = 1 W, P_out = 0.1 W.
Working: 10 log10(1/0.1) = 10 log10(10) = 10 × 1 = 10 dB. Answer: 10 dB.
Units/conclusion: dB. This shows signal loss, confirming attenuation is a reduction in signal strength.
Common mistake
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