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WorksheetsCHAPTER 4: THERMODYNAMIC CYCLES & SECOND LAW OF THERMODYNAMICS
Total questions: 10
Worksheet time: 5mins
What does the Second Law of Thermodynamics state about heat transfer?
A) Heat can spontaneously flow from cold to hot
B) Heat cannot be converted to work under any circumstances
C) Heat naturally flows from hot to cold without external influence
D) The total energy in a system is always decreasing
Which of the following represents the formula for thermal efficiency (ηη) of a heat engine?
A) η=Wnet.out/Qin
B) η=Qout/Qin
C) η=Qin/Wnet.out
D) η=1−(TL/TH)
A heat engine receives 200 kJ of heat and rejects 80 kJ. What is its thermal efficiency?
Which of the following is true for a Carnot cycle?
A) It consists of four reversible processes
B) It has an efficiency of 100%
C) It can be used to build a perpetual motion machine
D) It violates the Second Law of Thermodynamics
Which of the following equations correctly defines entropy change (ΔS)?
A) ΔS=∫dQ/T
B) ΔS=(Qin−Qout)/W
C) ΔS=W/Qin
D) ΔS=T⋅ΔQ
What is the COP (Coefficient of Performance) formula for a refrigerator?
A) COPR=QH/W
B) COPR=QL/W
C) COPR=W/QL
D)
COPR=(QH−QL)/QL
A Carnot engine operates between 600 K and 300 K. What is its thermal efficiency?
A) 25%
B) 33%
C) 50%
D) 66%
Which statement about entropy is correct?
A) Entropy always decreases in a closed system
B) Entropy measures the randomness or disorder of a system
C) Entropy is conserved in all real processes
D) Entropy is not related to energy dissipation
Which of the following is the correct efficiency formula for an ideal Carnot cycle?
A) η=(1−TL/TH)
B) η=W/QL
C) η=QH−QL
D) η=TH−TL
If a heat pump has a COP of 3 and the input work is 2 kW, how much heat is rejected to the high-temperature reservoir?
A) 2 kW
B) 4 kW
C) 6 kW
D) 8 kW
