Revision summary
Official key is (c) 1, 3 and 4 only. VLC/Li-Fi uses visible light (roughly 375–780 nm), can exceed 10 Gbps in tests, and does not add radio interference. It is a short-range, line-of-sight tool, not long-range optical wireless.
Model answer
Introduction
(a) 1, 2 and 3 only. VLC is typically short-range, not ‘long-range optical wireless’ as often worded.
Summary. Official key is (c) 1, 3 and 4 only. VLC/Li-Fi uses visible light (roughly 375–780 nm), can exceed 10 Gbps in tests, and does not add radio interference. It is a short-range, line-of-sight tool, not long-range optical wireless.
Body
- B
1, 2 and 4 only. Keeps the long-range miss.
- C
1, 3 and 4 only. Visible-spectrum EM, multi-Gbps lab rates, no radio EMI. Not a long-range system as statement 2 claims.
- D
2, 3 and 4 only. Drops the spectrum limb.
Summary. Official key is (c) 1, 3 and 4 only. VLC/Li-Fi uses visible light (roughly 375–780 nm), can exceed 10 Gbps in tests, and does not add radio interference. It is a short-range, line-of-sight tool, not long-range optical wireless.
Conclusion
Summary. Official key is (c) 1, 3 and 4 only. VLC/Li-Fi uses visible light (roughly 375–780 nm), can exceed 10 Gbps in tests, and does not add radio interference. It is a short-range, line-of-sight tool, not long-range optical wireless.
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