Basic knowledge on heat transfer |
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Please tick the correct answers: | |
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Heat transfer always occurs
when there are temperature differences. | The term "heat flux" means a movement. That's why it is only significant in a flowing transport mechanism such as convection. |
The higher the temperature difference of an object to the environment, the greater the flowing heat flux. | |
Heat always flows from hot to cold. | |
Only one heat transport mechanism ever provides for the temperature equalisation. | |
Even in a refrigerator, heat always flows from hot to cold. This does not contradict the ability to cool a space. | |
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The heat quantity is a property that a body has as soon as it has a temperature above absolute zero. How is this energy determined? | The heat quantity is dependent upon the mass. The substance is irrelevant. |
The heat quantity of a substance is dependent upon the temperature. | |
The ambient temperature is decisive for the heat quantity in a body. | |
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Conduction occurs when
substances with a temperature difference come into contact with each
other. | Temperature is the movement of the building blocks of matter. In the case of heat conduction, this movement is transferred to the surrounding matter. |
If no heat is added to or removed from a body, conduction ensures that the temperature is equalised and after some time is uniform in the body. | |
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Convection is the transport
of heat with a flowing particle. | Free convection denotes convection as it occurs in the open. Forced convection on the other hand represents the principle of free convection but forced in technical installations. |
Convection causes a temperature equalisation from the surface of a body into the environment. If no extra heat flows in, the temperatures equalize with each other. The heat exchange by convection becomes smaller and smaller. | |
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Radiation is known in everyday life from the
effect of the sun. | The universe consists of many celestial bodies (sun, planets, etc.) Heat can only be exchanged between these objects by radiation. |
Radiation cannot be inhibited. However, the effects can be ignored if dissipated and absorbed radiation have the same quantities. | |
