The danger signals installed at the top of tall buildings are red in colour. These can be easily seen from a distance because among all other colours, the red light

Why are danger signals red in colour ?

A rose appears red in light of all the colours.

Why are the 'danger signal' lights red in colour ?

Explain why danger signals are made of red colour ?

In an experiment, Pooja used a equilateral triangular glass prism and projected a narrow beam of white light source from one side of the surface of the prism. She placed a screen on the other side and saw many colours appearing as patches on the screen. But when she used a red light source, she could only see a red patch on the screen. Similarly she used a blue and green light source and could only see one colour patch on both occasions. The reason why she could no see any other colour when the red light was used was because: