Here is Question No. 39 a part of our series on UPSC Prelims 2020.
Q39. With reference to visible light communication (VLC) technology, which of the following statements are correct?
VLC uses the electromagnetic spectrum wavelengths 375 to 780nm
VLC is known as long-range optical wireless communication
VLC can transmit large amounts of data faster than Bluetooth
VLC has no electromagnetic interference.
Select the correct answer using the code given below (a) 1, 2 and 3 only (b) 1, 2 and 4 only (c) 1, 3 and 4 only (d) 2, 3 and 4 only
Answer: C
Visible Light Communication (VLC) technology is a wireless communication technology that utilizes light to transmit data and position between devices.
Statement 1 is correct: Li-Fi is a Visible Light Communications (VLC) system. Visible Light Communication (VLC) systems employ visible light for communication that occupy the electromagnetic spectrum from 375 nm to 780 nm.
Statement 2 is not correct: Long-range links are provided by optical fibre (also known as fiber optic cables), and links from the long-range end-points to end users are accomplished by RF wireless not by VLC.
Statement 3 is correct: VLC can transmit large amounts of data faster than Bluetooth. The VLC uses visible light for communication to provide high-speed internet up to 10 Gb/s while Bluetooth 4.0 promises speeds up to 25 Mb/s.
Statement 4 is correct: Without causing electromagnetic interference VLC has the advantage of being useful in electromagnetic-sensitive areas such as in aircraft cabins, hospitals, and nuclear power plants
