Exam-style question
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Which of the following best explains why optical fibre experiences less attenuation than copper cable?.
- A.Optical fibre has higher resistance.
- B.Light signals are not affected by electromagnetic interference.
- C.Optical fibre has a higher capacitance.
- D.Optical fibre uses thicker conductors.
Model answer
What a good answer should say
- Light signals are not affected by electromagnetic interference.
Explanation
Why this works
Formula: Attenuation (dB) = 10 log10(P_in/P_out). Substitution: P_in = 1 W, P_out = 0.9 W.
Working: 10 log10(1/0.9) = 10 log10(1.111) ≈ 10 × 0.0458 = 0.458 dB. Answer: 0.458 dB.
Units/conclusion: dB. Minimal attenuation due to lack of electromagnetic interference, showing optical fibre's advantage.
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