Why are danger signal lights red in colour?

Subject: General Science

Topic: The Human Eye and the Colourful World

Options:

1. Option A: Red light is easily visible
2. Option B: Red light is scattered the least by fog or smoke
3. Option C: Red light is scattered the most
4. Option D: Red light has the shortest wavelength

Correct Answer:

Option B: Red light is scattered the least by fog or smoke

Explanation:

Danger signal lights are red because red light is scattered the least by fog or smoke. Therefore, it can be seen from a distance even in adverse weather conditions.