{"id":86731,"date":"2025-06-01T04:19:38","date_gmt":"2025-06-01T04:19:38","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=86731"},"modified":"2025-06-01T04:19:38","modified_gmt":"2025-06-01T04:19:38","slug":"in-a-thermos-flask-the-walls-are-made-of-shiny-glass-which-one-of-th","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/in-a-thermos-flask-the-walls-are-made-of-shiny-glass-which-one-of-th\/","title":{"rendered":"In a thermos flask, the walls are made of shiny glass. Which one of th"},"content":{"rendered":"

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?<\/p>\n

[amp_mcq option1=”Convection” option2=”Conduction” option3=”Radiation” option4=”Both radiation and convection” correct=”option3″]<\/p>\n

\n
\n
This question was previously asked in<\/div>\n
UPSC Geoscientist – 2020<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
\nIn 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.
\n<\/section>\n
\nShiny surfaces are poor emitters and absorbers of thermal radiation, effectively reducing heat transfer by radiation.
\n<\/section>\n
\nA 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.
\n<\/section>\n","protected":false},"excerpt":{"rendered":"

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? [amp_mcq option1=”Convection” option2=”Conduction” option3=”Radiation” option4=”Both radiation and convection” correct=”option3″] This question was previously asked in UPSC Geoscientist – 2020 Download PDFAttempt Online In a thermos flask, the walls are made … <\/p>\n

Detailed SolutionIn a thermos flask, the walls are made of shiny glass. Which one of th<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1091],"tags":[1288,1130,1128],"class_list":["post-86731","post","type-post","status-publish","format-standard","hentry","category-upsc-geoscientist","tag-1288","tag-heat-and-thermodynamics","tag-physics","no-featured-image-padding"],"yoast_head":"\nIn a thermos flask, the walls are made of shiny glass. Which one of th<\/title>\n<meta name=\"description\" content=\"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. 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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. 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