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 lifespan 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.

Which of the following statements for persons suffering from presbyopia is/are correct ? 1. They cannot distinguish colours. 2. It usually develops with ageing. 3. They wear either bi-focal lenses co…

Which of the following statements with regard to the phenomenon of the primary rainbow formation by water droplets is/are correct ? 1. It involves refraction and one internal reflection of sunlight.…

A person can see near objects clearly through his eyes but cannot see distant objects clearly. The possible reason(s) for this defect could be: 1. Excessive curvature of the eye lens. 2. The eye-ball…

The streaming of light beams coming from the Sun through trees is said to have suggested that light travels in straight line. The particles on the path of light beams are visible to us because

Match the following lenses/mirrors with their correct applications. Column-I: i. Concave mirror ii. Convex mirror iii. Convex lens iv. Concave lens Column-II: p. Used in cameras and projectors for fo…