Question

Why red color is used in sign board

Answer 1

Becouse, Frequency of Red colour is lowest and it's wavelength it the longest among all visible colours.

That's why we can see it even from very far.

Answer 2

Heya !!

Here is your answer

Red colour is used in sign board because the wavelength of red colour is the most and frequency is less, so it is visible from far of distances during both day and night time.

Thank you !!

Hope it helps !!