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

NDA Physics

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


7.
Why is the interior of a thermos flask typically silvered?
A.
To reduce heat conduction
B.
To reduce heat radiation
C.
To enhance heat absorption
D.
To provide structural strength
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ANSWER :
A. To reduce heat conduction
8.
What type of energy transfer does the vacuum in a thermos flask specifically aim to minimize?
A.
Thermal radiation
B.
Mechanical work
C.
Electrical conduction
D.
Magnetic induction
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ANSWER :
A. Thermal radiation
9.
What is the role of the stopper in a thermos flask?
A.
To allow heat conduction
B.
To prevent liquid leakage and heat transfer
C.
To enhance heat radiation
D.
To improve the flask's durability
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ANSWER :
B. To prevent liquid leakage and heat transfer
10.
The outer case of a thermos flask is typically made of
A.
Glass
B.
Metal or plastic
C.
Rubber
D.
Wood
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ANSWER :
B. Metal or plastic
11.
Which of the following best describes the vacuum in a thermos flask?
A.
A space filled with gas
B.
A space with no air or matter
C.
A space with high pressure
D.
A space with solid insulation
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ANSWER :
B. A space with no air or matter
12.
The design of a thermos flask minimizes heat transfer through
A.
Multiple layers of insulation
B.
Double-walled construction with vacuum
C.
Single-walled design with foam
D.
Thick glass coating
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ANSWER :
B. Double-walled construction with vacuum