2021 Science & Technology - Lighting Technology

With reference to street-lighting, how do sodium lamps differ from LED lamps?1. Sodium lamps produce light in 360 degrees but it is not so in the case of LED lamps.2. As street-lights, sodium lamps have longer life span than LED lamps.3. The spectrum of visible light from sodium lamps is almost monochromatic while LED lamps offer significant colour advantages in street-lighting.Select the correct answer using the code given below.

• 3 only
• 2 only
• 1 and 3 only
• 1, 2 and 3