0
To reflect radiation back, where from it is coming. So hot contains will remain hot and cold will remain cold.
Wiki User
∙ 11y ago
Add your answer:
Earn +20 pts
How is heat loss by convection prevented in a thermal flask?
There is a layer of vacuum which surrounds the flask, then the inside is covered by shiny material which will reflect the heat back into the flask, there are two lids, and there is an indirect gap of about 0.01mm.
Vacuum is mantained in thermos flask?
The vacuum reduce heat loss by conduction and convection.
What is a vacuum flask made of?
A vacuum flask is a type of flask that aims to stop all three forms of heat transfer. Conduction, convection and radiation. A vacuum flask prevents conduction by making a vacuum between the inside and the outside layer of the flask, so that the only solids that touch are the lid and the main body of the flask. This means the amount of conduction that occurs is minimised. One major drawback though, is when the hot water transfers heat with the cold air inside the flask, then the hot air transfers heat with the cold lid, and then on the likely chance that the lid is hotter than the surroundings, the lid transfers heat with the air molecules around it. This means that a considerable amount of heat is lost to the surroundings. The only way convection can occur is by the hot liquid or solid transferring heat with the trapped air inside the flask, although this only affects the temperature of the water by a bit, because most of the liquid condenses again. The flask is made so that radiation is reflected back of the sides, which is made of a shiny material. Also, the flask is not transparent; it is made of an opaque material, usually plastic or metal. The only way radiation can escape, is by the lid being taken off.
How is heat transferred away from a vacuum flask?
a vacuum flask is not 100% vacuum. it contains some particles or gas molecules which absorbs a small amount of heat.
How does a thermos flask reduce heat loss by radiation?
Vaccum between thermos walls does NOT prevent radiation, however the other forms of heat transfer(convection and conduction) are more or less eliminated. Radiation effect of heat transfer may be reduced by applying a layer of reflective material inside the bootles - to reflect the emmision back inwards.
How is heat loss by convection prevented in a thermal flask?
There is a layer of vacuum which surrounds the flask, then the inside is covered by shiny material which will reflect the heat back into the flask, there are two lids, and there is an indirect gap of about 0.01mm.
Why are shiny outer surfaces needed in a vacuum flask?
The outer surfaces do not need to be shiny. The interior ones do, to reflect heat back rather than let the heat pass out of the vacuum flask. The vacuum between the double walls of the flask also reduces heat loss.
The color of a vacuum flask in the inside?
white
Vacuum is mantained in thermos flask?
The vacuum reduce heat loss by conduction and convection.
Which form of heat transfer is reduced by the use of vacuum inside a vacuum flask?
The vacuum reduces both conduction and convection.
How does a vacuum flask reduce heat loss from a hot liquid inside?
Due to open space isolating the flask from external temperature
Why is the inside part of the thermos flask shiny?
It helps to insulate the thing inside the thermo flask. The heat or coldness outside the flask gets reflected away. It might sound silly but it is true
What can travel through shiny convention or conduction?
A shiny surface will reflect light and heat, and thus is not a conductor. This property is used in a vacuum flask. If a shiny surface is in intimate contact with a hot object, then thermal conduction will take place.
How do you deal with the liquid mercury scattered in laboratory?
Set up a vacuum flask with flexible intake tubing long enough to reach the mercury spill. Use glass tubing on the inside of the flask to reach nearly to the bottom on the intake side. On the other side (the side connected to the vacuum source) make sure the glass tubing reaches just inside the flask, near the top, so that the mercury entering the flask will not simply be sucked into the vacuum source lines. Use a two-holed rubber stopper to accomplish all this. This will give you a mercury vacuum cleaner, so to speak. Use a regulator and be careful to use just enogh vacuum to lift the mercury into the flask.
What is a vacuum flask made of?
A vacuum flask is a type of flask that aims to stop all three forms of heat transfer. Conduction, convection and radiation. A vacuum flask prevents conduction by making a vacuum between the inside and the outside layer of the flask, so that the only solids that touch are the lid and the main body of the flask. This means the amount of conduction that occurs is minimised. One major drawback though, is when the hot water transfers heat with the cold air inside the flask, then the hot air transfers heat with the cold lid, and then on the likely chance that the lid is hotter than the surroundings, the lid transfers heat with the air molecules around it. This means that a considerable amount of heat is lost to the surroundings. The only way convection can occur is by the hot liquid or solid transferring heat with the trapped air inside the flask, although this only affects the temperature of the water by a bit, because most of the liquid condenses again. The flask is made so that radiation is reflected back of the sides, which is made of a shiny material. Also, the flask is not transparent; it is made of an opaque material, usually plastic or metal. The only way radiation can escape, is by the lid being taken off.
What is vacuum cup?
it is the cup that comes on a vacuum flask
Substance that contains the vacuum in a vacuum flask?
Glass
