Heat NEET Questions

Physics - Thermodynamics

Heat MCQ Questions


7.
Heat supplied to a system can be identified experimentally as:
A.
The change in pressure of the system
B.
Any energy exchange between a system and surroundings
C.
The work done by surrounding atmosphere on the system
D.
Energy transfer driven by a temperature difference between the system and its surroundings (without mechanical action)
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ANSWER :
D. Energy transfer driven by a temperature difference between the system and its surroundings (without mechanical action)
8.
According to NCERT's sign convention, ΔQ > 0 means:
A.
Work is done by the system
B.
Internal energy decreases
C.
Heat is supplied TO the system by the surroundings
D.
Heat is removed from the system
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ANSWER :
C. Heat is supplied TO the system by the surroundings
9.
Which of the following correctly describes the relationship between the old unit 'calorie' and the SI unit 'joule' for heat?
A.
1 joule = 4.186 calories
B.
1 calorie = 1 joule
C.
1 calorie = the heat to raise 1 g water from 14.5°C to 15.5°C = 4.186 J
D.
1 calorie = 4.186 kJ
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ANSWER :
C. 1 calorie = the heat to raise 1 g water from 14.5°C to 15.5°C = 4.186 J
10.
The 'mechanical equivalent of heat' is a term used in older physics. In modern SI units, this term is:
A.
Still important — it equals 4186
B.
Defined as the ratio of work to heat
C.
Only applicable to gases
D.
Superfluous — since SI uses joule for both heat and work, there is no need for a conversion factor
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ANSWER :
D. Superfluous — since SI uses joule for both heat and work, there is no need for a conversion factor
11.
In the First Law of Thermodynamics ΔQ = ΔU + ΔW, what does ΔQ specifically represent?
A.
Work done by the system on surroundings
B.
Heat rejected by the system
C.
Change in internal energy alone
D.
Total heat supplied to the system by the surroundings
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ANSWER :
D. Total heat supplied to the system by the surroundings
12.
In an isothermal process for an ideal gas (ΔT = 0), the heat supplied ΔQ equals:
A.
ΔU only (all heat goes to internal energy)
B.
ΔW (work done by gas) — since ΔU = 0 for ideal gas at constant temperature
C.
2ΔW
D.
Zero — no heat flows in isothermal process
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ANSWER :
B. ΔW (work done by gas) — since ΔU = 0 for ideal gas at constant temperature