The cooling fins at the back of refrigerator are made of black and rough surface because ?

B. They are good radiators of heat

A. They are good absorbers of heat

B. They are good radiators of heat

C. They prevent dust accumulation

D. They are cheaper to manufacture

The ratio of the heat accepted to the heat rejected by a Carnot engine is equal to?

B. The ratio of the temperatures of the source and sink

A. The efficiency of the working substance

B. The ratio of the temperatures of the source and sink

C. The square of the efficiency

Which of the following does not affect the boiling point?

C. Initial temperature of the liquid

What is heat energy the result of?

D. Movement of tiny particles like atoms, molecules, or ions

A. Absorption of light by a surface

B. Flow of electric charges through a conductor

C. Chemical reaction between two substances

D. Movement of tiny particles like atoms, molecules, or ions

Everyday Science · Physics in Everyday Life · page 18 of 41

Heat & Thermodynamics MCQs with Answers

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Heat & Thermodynamics MCQs (171–180)

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Past paper MCQs in this chapter · See all past papers

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171.
Temperature of healthy person is 37°C. What is this temperature on Kelvin scales?
Correct Answer: A. 310 K
One-liner
The normal human body temperature of 37°C is equal to 310 K on the Kelvin scale.
172.
The cooling fins at the back of refrigerator are made of black and rough surface because ?
Correct Answer: B. They are good radiators of heat
One-liner
The cooling fins at the back of a refrigerator are made black and rough because they are good radiators of heat.
173.
Bursting of iron is an example of which process?
Correct Answer: C. Adiabatic
One-liner
Bursting of iron is an example of an adiabatic process, where a rapid change occurs without any heat exchange with the surroundings.
174.
The ratio of the heat accepted to the heat rejected by a Carnot engine is equal to?
Correct Answer: B. The ratio of the temperatures of the source and sink
One-liner
The ratio of heat accepted (Q₁) to heat rejected (Q₂) by a Carnot engine equals the ratio of the temperatures of the source and sink (T₁/T₂).
175.
Which of the following does not affect the boiling point?
Correct Answer: C. Initial temperature of the liquid
One-liner
The boiling point of a liquid is not affected by its initial temperature, as boiling occurs at a fixed temperature under constant pressure regardless of the starting temperature.
176.
Freezing point of water is ?
Correct Answer: D. All of these
One-liner
The freezing point of water is All of these — 0°C, 32°F, and 273 K all represent the same temperature.
177.
The heat content of the system is known as _?
Correct Answer: B. Enthalpy
One-liner
The heat content of a system at constant pressure is known as Enthalpy.
178.
What is heat energy the result of?
Correct Answer: D. Movement of tiny particles like atoms, molecules, or ions
One-liner
Heat energy is the result of the movement of tiny particles like atoms, molecules, or ions.
179.
Which substance expands the most for the same rise in temperature?
Correct Answer: C. Air
One-liner
Air (a gas) expands the most for the same rise in temperature because gases have weaker intermolecular forces and higher thermal expansion coefficients compared to liquids and solids.
180.
What is the boiling point of water at standard atmospheric pressure?
Correct Answer: A. 100°C
One-liner
The boiling point of water at standard atmospheric pressure (1 atm or 760 mmHg) is 100°C (212°F).

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Heat & Thermodynamics MCQs with Answers

Heat & Thermodynamics MCQs (171–180)

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