Optical Fibres
2 marks · NormalA telecommunications company wants to replace copper wires with optical fibres. Give two reasons, based on physics, why optical fibres are better for transmitting signals over long distances.
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Also accept: Less energy/signal is lost in optical fibres than copper wires.; Optical fibres are not affected by electromagnetic interference.
Common mistakes: Answers not focused on physical principles.
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Marking points
B1 · 1 mark · States less signal/energy loss over distance in optical fibres.
B1 · 1 mark · States optical fibres are not affected by electromagnetic interference (or give other valid physics reason: e.g., higher bandwidth, more information transmitted).
Worked solution
Optical fibres lose less energy or signal than copper wires, so they are more efficient for long-distance transmission. They are also immune to electromagnetic interference, so signals are clearer and less likely to be disrupted.