With reference to Visible Light Communication (VLC) technology, which of the following statements are correct?

1. VLC uses electromagnetic spectrum wavelengths 375 to 780 nm.
2. VLC is known as long-range optical wireless communication.
3. VLC can transmit large amounts of data faster than Bluetooth.
4. VLC has no electromagnetic interference.

Select the correct answer using the code given below:

[UPSC Civil Services Exam – 2020 Prelims]

(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)        

Explanation:

Visible Light Communication Technology

• It is a wireless method that enables high-speed transmission of data with visible light.
• It makes use of Visible Light spectrum. It occupies the spectrum from 380 nm to 750 nm. Hence statement 1 is correct.
• It enables high-speed internet access primarily in the indoor environment.
• It works on the principle of intensity modulation of existing solid-state lighting infrastructure often provided by light-emitting diodes.
• The nature of light is that it is unable to pass through opaque walls. Hence, VLCT is used in indoor environment/short range. Hence statement 2 is not correct.
• Li-Fi can transmit large amounts of data faster than Bluetooth and wi-fi. Hence statement 3 is correct.
• VLC systems operate at optical frequencies and emit no electromagnetic interference. Therefore, it can be used in Healthcare services. Hence statement 4 is correct.