Q. Red is used as an emergency or danger signal as
✅ Correct Answer: (B)
Its wavelength is the longest
Explanation: Danger signals are red in color because it is scattered the least by air molecules. Since the color red has the highest wavelength of all the colors we can see it scattered the least. So, red light is used as a danger signal as it is able to travel the longest distance through the fog, rain, etc.
Explanation by: Team MCQ Buddy
Danger signals are red in color because it is scattered the least by air molecules. Since the color red has the highest wavelength of all the colors we can see it scattered the least. So, red light is used as a danger signal as it is able to travel the longest distance through the fog, rain, etc.