we know that only infrared is responsible for heat in sun light . Colour of infrared is not visible. Only white doesn't sense that it will reflect infrared or not. Then how can I say that white colour cloth is better in summer?
You are right. But people have discovered that since white reflects almost all colours (that is why it appears white) the chances of it reflecting infrared are also more and surfaces painted white have been found to be cooler inside. But an interesting thing is that Bedouins , a nomadic desrt tribe wear black and it has been found to be cooler.there. But that is because of some air current set up. It is explained in one of the editions of Resnick Halliday (6th i think).
And let us just hope that the best reflector of infra-red is not transparent to visible light!