In a thermos flask, the walls are made of shiny glass. Which one of th

In a thermos flask, the walls are made of shiny glass. Which one of the following heat loss process is minimised by using shiny walls?

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Convection

Conduction

Radiation

Both radiation and convection

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Answer is Wrong!

This question was previously asked in

UPSC Geoscientist – 2020

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In a thermos flask, the walls are made of shiny glass to minimise heat loss by radiation. Shiny surfaces are poor emitters and poor absorbers of thermal radiation. By making the inner and outer surfaces shiny, heat transfer by radiation is significantly reduced. Heat from the hot liquid inside is not easily radiated outwards, and external heat is not easily absorbed and radiated inwards.

Shiny surfaces are poor emitters and absorbers of thermal radiation, effectively reducing heat transfer by radiation.

A thermos flask is designed to minimise all three modes of heat transfer: conduction (by using a vacuum between the walls and a stopper), convection (by using a vacuum and a narrow neck), and radiation (by using shiny surfaces and a vacuum). The shiny walls specifically target the reduction of heat transfer through radiation.

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