Reversible and Irreversible Processes NEET Questions

Physics - Thermodynamics

Reversible and Irreversible Processes MCQ Questions


13.
Heat flowing from a hot base of a vessel to its cooler upper parts is described in NCERT as irreversible because:
A.
The vessel changes its chemical composition
B.
The reverse process — a part of the vessel getting cooler spontaneously while the base warms — violates the Second Law (Clausius statement)
C.
Heat conduction in solids is always reversible
D.
Only heat through radiation can be reversed
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ANSWER :
B. The reverse process — a part of the vessel getting cooler spontaneously while the base warms — violates the Second Law (Clausius statement)
14.
An explosive chemical reaction (e.g., petrol vapour and air ignited by a spark) is irreversible because:
A.
The spark cannot be re-applied
B.
The reaction is too slow
C.
The reaction takes the system to highly non-equilibrium states; pressure and temperature are not uniform — and the products cannot spontaneously reassemble into reactants
D.
The reaction produces too much heat
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ANSWER :
C. The reaction takes the system to highly non-equilibrium states; pressure and temperature are not uniform — and the products cannot spontaneously reassemble into reactants
15.
Gas diffusing from a cylinder to fill an entire room is listed in NCERT as an example of an irreversible process. The process cannot spontaneously reverse because:
A.
The reverse (all gas spontaneously returning to the cylinder) has an astronomically low probability — it would also violate the Second Law
B.
Gas molecules are attracted to the cylinder walls
C.
Gravity prevents gas from entering the cylinder
D.
The cylinder is too small for the gas
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ANSWER :
A. The reverse (all gas spontaneously returning to the cylinder) has an astronomically low probability — it would also violate the Second Law
16.
The most significant consequence of reversibility for heat engines is:
A.
Reversible engines operate faster than irreversible ones
B.
Reversible engines violate the First Law
C.
A heat engine based on idealised reversible processes achieves the highest possible efficiency — all irreversible engines have lower efficiency
D.
Reversible engines do not need a cold reservoir
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ANSWER :
C. A heat engine based on idealised reversible processes achieves the highest possible efficiency — all irreversible engines have lower efficiency
17.
A thermodynamic process can be reversible only if it is quasi-static. Why does a non-quasi-static process fail the reversibility test?
A.
Non-quasi-static processes have ΔU = 0 always
B.
Non-quasi-static processes happen at constant temperature
C.
Non-quasi-static processes are always adiabatic
D.
In a non-quasi-static process, the system passes through non-equilibrium states where P and T are not well-defined, making exact reversal impossible
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ANSWER :
D. In a non-quasi-static process, the system passes through non-equilibrium states where P and T are not well-defined, making exact reversal impossible
18.
In a quasi-static process, the condition imposed on pressure is:
A.
Pressure is always maximum
B.
Pressure is always zero
C.
At every stage, the difference between the system's pressure and external pressure is infinitesimally small
D.
Pressure is constant throughout
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ANSWER :
C. At every stage, the difference between the system's pressure and external pressure is infinitesimally small