Q1. Consider the following statements about Li-Fi: (I) It uses normal bulbs to transfer data. (II) This technology uses the visible spectrum of light. (III) The speed of Li-Fi is slower than Wi-Fi. (IV) It is expected to be cheaper than Wi-Fi. Choose the correct statement.
Explanation
Li-Fi transmits data through light, and its working range lies in the visible light spectrum, so the statement about visible spectrum use is correct. It is also generally expected to be cheaper in deployment where lighting infrastructure already exists. The statement about using normal bulbs is imprecise because Li-Fi needs suitably modulated LED lamps, not ordinary bulbs in the usual sense. Li-Fi is not slower than Wi-Fi; it is known for very high data-transfer speed under suitable conditions. Therefore, the pair containing visible spectrum and lower expected cost fits the given key.