WorksheetsThermo2 - Laws of Thermodynamics
Total questions: 25
Worksheet time: 25mins
What does the first law of thermodynamics state?
Energy can be created and destroyed
Energy cannot be created or destroyed, only transformed
Energy can be created but not destroyed
Energy is always conserved in isolated systems
Which equation represents the first law of thermodynamics?
ΔU=Q+W
ΔU=Q−W
ΔU=W−Q
ΔU=Q×W
Which of the following is an example of a process that obeys the first law of thermodynamics?
Perpetual motion machines
Conservation of mass
A closed system where heat added equals the work done by the system plus change in internal energy
An isolated system where heat is continuously produced without work
The second law of thermodynamics states that:
Total energy is conserved in a system
Entropy of an isolated system always decreases
Entropy of an isolated system never decreases
Energy can neither be created nor destroyed
In an adiabatic process:
Heat is transferred to the surroundings
No heat is transferred to or from the system
Work is done on the system without changing its internal energy
Temperature remains constant
What is the symbol for internal energy?
Q
W
U
H
In the first law of thermodynamics, what does WWW represent?
Work done by the system
Work done on the system
Heat absorbed by the system
Heat released by the system
The efficiency of a Carnot engine is determined by:
The difference in volume of the gas
The temperatures of the heat reservoirs
The type of gas used
The amount of work done
Which of the following is true for an isothermal process?
Temperature remains constant
Pressure remains constant
Volume remains constant
Entropy remains constant
Entropy can be best described as:
The total energy of a system
A measure of disorder or randomness
The amount of work done by a system
The heat transferred in a process
During an isobaric process:
Pressure remains constant
Volume remains constant
Temperature remains constant
Entropy remains constant
Which statement about heat engines is true?
All heat engines have the same efficiency
A heat engine cannot convert all heat energy into work
Heat engines can have 100% efficiency
Work done by a heat engine equals the total heat input
In the context of the second law of thermodynamics, what is a reversible process?
A process that happens spontaneously
A process that can be reversed without any change in entropy
A process that only occurs in closed systems
A process that does not involve heat transfer
The second law of thermodynamics implies that:
Energy flows from colder to hotter bodies
Energy flows from hotter to colder bodies
Work is completely converted to heat
Heat engines operate without any waste heat
The Clausius statement of the second law of thermodynamics states that:
It is impossible to construct a heat engine that operates without exhaust
It is impossible to construct a heat engine that operates with 100% efficiency
Heat cannot spontaneously flow from a colder body to a hotter body
Entropy always increases in an isolated system
Which of the following is NOT a form of the first law of thermodynamics?
Energy conservation
ΔU=Q+W
ΔU=Q−W
ΔE=Ein−Eout
Which of the following expressions represents the efficiency of a heat engine?
η=Wout/Qin
η=Qout/Qin
η=Qin/Qout
η=Wout/Qout
The efficiency of a Carnot engine operating between two heat reservoirs at temperatures T1 and T2 (where T1>T2) is given by:
1−T1/T2
1+T2/T1
1−T2/T1
(T1−T2)/T1
The change in entropy for a reversible isothermal process is given by:
ΔS=Q/T
ΔS=Q⋅T
ΔS=Q⋅ΔT
ΔS=T/Q
Which of the following is true for a closed system undergoing a cycle?
The net work done is zero
The change in internal energy is zero
The net heat added is zero
The change in entropy is zero
In a cyclic process, the total change in internal energy over one complete cycle is:
Zero
Equal to the heat added
Equal to the work done
Equal to the entropy change
The Kelvin-Planck statement of the second law of thermodynamics states that:
It is impossible to convert all of the energy from a heat source into work
It is impossible to transfer heat from a cold body to a hot body
The entropy of an isolated system never decreases
Energy is conserved in all processes
The coefficient of performance (COP) of a refrigerator is defined as:
COP=QH/W
COP=W/QL
COP=QL/W
COP=QH−QL/W
In an isolated system, the total entropy change is:
Always positive or zero
Always negative
Always zero
Always positive
Which of the following best describes the principle of entropy increase?
In any reversible process, the total entropy remains constant
In any natural process, the total entropy of the system and its surroundings always increases
Entropy can never be created or destroyed
The entropy of a system can decrease only if the entropy of its surroundings increases
