Question

Red light is used as a danger signal because it is:
A. Accepted as symbol
B. Pleasing to the eye
C. Sensitive to the eye
D. Having a high wavelength

Answer 1

In this question, we need to comment on the reason why red light is used as a danger signal. Red light has the highest wavelength among all colours of lights. We know when the spectrum of visible light is passed through the prism; then the wavelength separates into the colour of the spectrum since each colour has a different wavelength. Violet has the shortest wavelength, and the red has the longest wavelength.

Complete step by step answer:

We know that the red light has the highest wavelength among all colour of lights which means the distance between the two crests will be the longest so this light will scatter the least, and the scattering of this light is less, so the most of this light gets reflected, and this can travel longer distances. This light can even travel through rain, fog, dust.
Hence we can say red light is used as a danger signal because it has a high wavelength

So, the correct answer is “Option D”.

Note:
The wavelength of the light is the distance between the two crests and the troughs. Students must note that the light which has the highest wavelength will have a lower frequency and the light which has the shortest wavelength will have a higher frequency.