Question

why are people advised to use umbrella when they go out in the sun?

Answer 1

Umbrellas protect the person from getting in direct contact of the sun's rays, as they block the sun's rays and thus, the temperature below the umbrella is cool as compared to outside it. The outer cover of umbrella is painted black and the inner surface is painted silver, as silver reflects back the heat absorbed by the black surface and thus, we feel cool under an umbrella and get protection from the harmful UV rays also.