white colored body reflects the sunlight back whaere as black body absords and radiates perfectly, if umbrella’s are made in white color then the heat caused by sunlight won’t be radiated into inside of umbrella .but why can’t umbrella’s are made in white color ?

It`s not that difficult umbrellas can`t be made of white colour but it is due to reflection and absorption. Although white is good reflector, it cannot reflect back whole of the radiations. This will not provide complete shade and also heat up the person holding it. This is also because pure white is never available. But black or any other dark colour would absorb most of the radiations and will emit them back. On checking an umbrella from inside, it is found to be silvered. It is so because small amount of radiations which are not absorbed by dark side are reflected back to the dark part. Thus this this reduces the radiations reaching us by 99%.This will keep us cool.