Advertisements
Advertisements
Question
Draw a labelled diagram of a thermo flask. Explain how the transfer of heat by conduction, convection and radiation is reduced to a minimum in it.
Advertisements
Solution
Heat transfer is minimised because of:
(1) The vacuum between the two walls, rubber, glass, cork and air do not allow the loss of heat by conduction.
(2) Cork in the neck of flask and the cup over it prevent loss of heat by convection.
(3) Heat cannot be lost by conduction or convection because of vacuum between the two walls.
(4) Heat loss is also minimised by radiation, by making outer surface of inner wall and inner surface of outer wall silvered. The inner wall is a BAD RADIATOR and the outer wall is a GOOD REFLECTOR of radiation.
APPEARS IN
RELATED QUESTIONS
What is heat ? State its S.I. unit.
While deciding the unit for heat, which temperature interval is chosen? Why?
What will absorb heat?
Steel spoon
What will absorb heat?
Wax
When an object is heated, the molecules that make up the object
A device in which the loss of heat due to conduction, convection and radiation is minimized is ______.
The SI unit of heat energy is ______.
Arrange the following in order of decreasing the expansion of heating: Steel, milk, air.
On a cold day, it is hard to open the lid of a tight container. But when you gently heat the neck you can easily open the lid. why?
Explain the following effects of heat.
Chemical changes
