Question

why danger signals always showing red light? pls help me with this

Answer 1

because wavelength of red colour is large, therefore, it is least scattered. Hence, it can be seen from maximum distance.

Answer 2

Because the wavelength of red light is more than any other colour. It does not get scatter much by the atmospheric particles easily, while other colours do. Red, green and blue are the 3 basic colors which in combination produce other colors. Amongst these, red is the color with the longest wavelength which causes it to scatter less while travelling thorough air. Hence, red light is visible from a long distance and so it is used to indicate danger. I hope you will better understand now .