在城市街道路口和铁路线上,交通信号为什么都是红、黄、绿三种颜色呢?这是人们经过研究和实验并根据光学原理而确定下来的。在红、橙、黄、绿、青、蓝、紫7种颜色中,以红色光波最长。光波越长,它穿透周围介质的能力就越大。因此,在光度相同的条件下,红色显示得最远,人们对红色 Why are the traffic signals red, yellow and green at the intersection of the city streets and the railway line? This is the result of research and experiments conducted by people on the basis of optical principles. Among the seven colors of red, orange, yellow, green, cyan, blue and violet, the red light wave is the longest. The longer the light wave, the greater its ability to penetrate the surrounding medium. Therefore, under the same luminosity conditions, the red color is the longest and people are red