General Principles in the Working of Thermos Flask, Gramophone NDA Questions

NDA Physics

General Principles in the Working of Thermos Flask, Gramophone MCQ Questions


1.
What is the primary function of a thermos flask?
A.
To cool beverages
B.
To filter impurities
C.
To maintain the temperature of liquids
D.
To increase the volume of liquids
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ANSWER :
C. To maintain the temperature of liquids
2.
Which principle does a thermos flask primarily use to maintain temperature?
A.
Evaporation
B.
Radiation
C.
Insulation
D.
Convection
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ANSWER :
C. Insulation
3.
The vacuum between the walls of a thermos flask prevents heat transfer by
A.
Conduction and convection
B.
Conduction and radiation
C.
Convection and radiation
D.
Conduction, convection, and radiation
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ANSWER :
A. Conduction and convection
4.
What material is commonly used for the inner lining of a thermos flask?
A.
Glass
B.
Plastic
C.
Aluminium
D.
Copper
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ANSWER :
A. Glass
5.
Who is credited with inventing the thermos flask?
A.
Albert Einstein
B.
James Dewar
C.
Thomas Edison
D.
Michael Faraday
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ANSWER :
B. James Dewar
6.
The outer surface of the inner bottle of a thermos flask is usually
A.
Rough
B.
Polished
C.
Painted
D.
Insulated with foam
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ANSWER :
B. Polished