Question

Why are red-colored lights used in traffic signals to stop the vehicles?

A. Minimum wavelength and less scatter

B. Maximum wavelength and more scatter

C. Maximum wavelength and less scatter

D. Less wavelength and less scatter

Answer 1

Hint: Red color is one of the most prominent colors in the visible reign and it is a highly stimulated color among the other colors. It is a part of the VIBGYOR pattern observed when white light undergoes dispersion.

Complete Step by step solution

Dispersion is a phenomenon in which when white light passes through any prismatic transparent object it splits into seven distinguishable color bands in which we can observe that the red-colored band deviates less than other colors which shows that it has a maximum wavelength.

Now as we know that scattering is a phenomenon in which white light gets deviated from its straight path when it strikes obstacles such as dust particles, water molecules, and other gas molecules present in the medium. The scattering of light depends on the size of particles present in the medium compared to the wavelength of light. More the wavelength less the scattering and vice versa.

As discussed, red light having maximum wavelength scatters less when it passes through any medium as a result it is widely used in many applications such as in traffic lights and because it can be seen from far away by drivers. Even in the fog, it can be seen from far as due to its maximum wavelength it travels a longer distance and scatters less.

Hence option (C) is the correct answer.

Note: Scattering phenomena are also observed in nature like the red color of the sky during sunset and sunrise. As a red color having maximum wavelength it experiences less scattering along its path when passing through the atmosphere as a result the sky appears red during sunset and sunrise.