Usually, umbrellas are Black and black colour absorbs heat.Then why do we use black umbrellas to get protected from the sun?
To really understand what's going on here, you want to understand how light is emitted and absorbed. Essentially, when the light is absorbed, a photon of light comes in and hits an electron, giving it some energy.
Now whether it’s absorbed or not will depend on the structure of the electrons [in the atom]. If there's somewhere for the electron to go, and if it can increase its energy level, then it will absorb the light. If not, then the light can't be absorbed and carries straight on. If it is absorbed, the substance looks black. If it isn't, it’s white [because the light is reflected back].
This means that, if you heat something up, if there's [a higher energy level] somewhere for the electrons to go up to, and it’s black, then there's also somewhere for the electron to drop down to again, meaning that the substance will also emit energy.
So if something is good at absorbing light then it’s also good at emitting it. So a black thing should be much better emitting light than a white thing.
Hence, black umbrella absorbs more energy and simultaneously it also emits more energy, thus maintaining the temperature of the black body.
To really understand what's going on here, you want to understand how light is emitted and absorbed. Essentially, when the light is absorbed, a photon of light comes in and hits an electron, giving it some energy.
Now whether it’s absorbed or not will depend on the structure of the electrons [in the atom]. If there's somewhere for the electron to go, and if it can increase its energy level, then it will absorb the light. If not, then the light can't be absorbed and carries straight on. If it is absorbed, the substance looks black. If it isn't, it’s white [because the light is reflected back].
This means that, if you heat something up, if there's [a higher energy level] somewhere for the electrons to go up to, and it’s black, then there's also somewhere for the electron to drop down to again, meaning that the substance will also emit energy.
So if something is good at absorbing light then it’s also good at emitting it. So a black thing should be much better emitting light than a white thing.
Hence, black umbrella absorbs more energy and simultaneously it also emits more energy, thus maintaining the temperature of the black body.
