Nos supermercados, os congeladores horizontais que guardam alimentos supergelados não necessitam de porta e os verticais necessitam. A explicação para esse fato é que nos congeladores horizontais:
- A) o ar frio, mais denso, que fica sobre o congelador isola os alimentos do calor exterior;
- B) o calor vai sendo conduzido da zona de menor temperatura para a de maior temperatura;
- C) o gelo depositado sobre os alimentos impede a propagação do calor por convecção;
- D) a irradiação do frio se dá por ondas eletromagnéticas que ficam concentradas sobre o congelador;
- E) o ar quente do exterior não atinge os alimentos porque não consegue romper a tensão superficial do ar frio.
Resposta:
Hey there! Let's dive into the world of thermodynamics and explore why horizontal freezers don't need doors, while vertical ones do. The correct answer is option A) the cold, denser air that settles on top of the horizontal freezer isolates the food from external heat.
In horizontal freezers, the cold air is denser and heavier than warm air. As a result, it settles at the bottom of the freezer, creating a layer of cold air that prevents warm air from entering the freezer. This natural convection process ensures that the cold air remains close to the frozen food, keeping it at a stable temperature. Since the cold air is in contact with the food, it absorbs heat from the food, maintaining a consistent refrigeration temperature.
On the other hand, vertical freezers have a different airflow pattern. The cold air is not as dense and tends to rise, allowing warm air to enter the freezer more easily. Without a door, the warm air would constantly enter the freezer, causing the temperature to fluctuate and affecting the quality of the frozen food. That's why vertical freezers need doors to maintain a consistent temperature and prevent warm air from entering the freezer.
In summary, the correct answer is option A) because the cold, denser air that settles on top of the horizontal freezer isolates the food from external heat, making it unnecessary to have a door. This natural convection process ensures that the cold air remains close to the frozen food, maintaining a consistent refrigeration temperature.
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