UPSC Prelims 2020 Question:

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:

Explanation:

• Visible Light Communication (VLC) is a variant of data communication that utilises visible light between the intensity of 375-780 THz. It is a type of wireless communication technology. Under this technology, fluorescent light is used to transmit signals at 10 kbit/s and LED lights are used to transmit 500 Mbit/s over a small distance. So, statement 1 is correct.
  
  
• Since VLC uses visible light for data transmission, it will be able to transmit data only when there are no opaque obstacles in its way. Thus, VLC cannot be used for long-range optical wireless communication. So, statement 2 is not correct. 
  
  
• A Bluetooth supported device can transmit data at the maximum rate of kilobytes per second (kbps). On the other hand, VLC is a far advanced way of communication and it is able to transmit data in the range gigabytes per second (gbps). So, statement 3 is correct.
  
  
• Use of Wi-Fi is prohibited inside hospitals as it can interfere with medical devices such as MRI and even treatment of patients. On the other hand, technology such as Li-Fi offers a feasible opportunity where visible light communication can enable data transfer in such EMI (Electromagnetic Interference) sensitive environments. So, statement 4 is correct.
  
  

Therefore, option (3) is the correct answer.

Subject: Science & Technology | Information and Communication Technology