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85 kJ of heat is supplied to a closed system at constant volume. During the next process, the system rejects 90 kJ of heat at constant pressure while 20 kJ of work is done on it. The system is brought to the original state by an adiabatic process. The initial internal energy is 100 kJ. Then what is the quantity of work transfer during the process?
  • a)
    30 kJ
  • b)
    25 kJ
  • c)
    20 kJ
  • d)
    15 kJ
Correct answer is option 'D'. Can you explain this answer?
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85 kJ of heat is supplied to a closed system at constant volume. Durin...
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85 kJ of heat is supplied to a closed system at constant volume. Durin...
For constant volume , work is 0
u1- u2=Q
initial internal energy u1 is 100kj
find u2
after this for contant pressure
Q=W+(U1-U2)
FIND U1-U2 OR CHANGE IN INTERNAL ENERGY.
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85 kJ of heat is supplied to a closed system at constant volume. Durin...
Given:
Heat supplied to the system at constant volume: 85 kJ
Heat rejected from the system at constant pressure: 90 kJ
Work done on the system: 20 kJ
Initial internal energy: 100 kJ

To find: Quantity of work transfer during the process

The first law of thermodynamics states that the change in internal energy of a closed system is equal to the heat added to the system minus the work done by the system:

ΔU = Q - W

where ΔU is the change in internal energy, Q is the heat added to the system, and W is the work done by the system.

In this case, the system undergoes two processes: constant volume and constant pressure. Let's analyze each process separately:

1. Constant volume process:
During this process, 85 kJ of heat is supplied to the system. Since the volume is constant, no work is done by the system. Therefore, the change in internal energy is equal to the heat added:

ΔU1 = Q1 = 85 kJ

2. Constant pressure process:
During this process, 90 kJ of heat is rejected from the system and 20 kJ of work is done on the system. The change in internal energy can be calculated using the first law of thermodynamics:

ΔU2 = Q2 - W2
= -90 kJ - 20 kJ
= -110 kJ

Note that the negative sign indicates a decrease in internal energy.

Now, to find the total change in internal energy of the system, we need to add the changes from both processes:

ΔU_total = ΔU1 + ΔU2
= 85 kJ - 110 kJ
= -25 kJ

Since the system is brought back to its original state by an adiabatic process (no heat transfer), the change in internal energy must be zero. Therefore, the work transfer during the process can be calculated as:

W_total = -ΔU_total
= 25 kJ

Therefore, the quantity of work transfer during the process is 25 kJ, which corresponds to option D.
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85 kJ of heat is supplied to a closed system at constant volume. During the next process, the system rejects 90 kJ of heat at constant pressure while 20 kJ of work is done on it. The system is brought to the original state by an adiabatic process. The initial internal energy is 100 kJ. Then what is the quantity of work transfer during the process?a)30 kJb)25 kJc)20 kJd)15 kJCorrect answer is option 'D'. Can you explain this answer?
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85 kJ of heat is supplied to a closed system at constant volume. During the next process, the system rejects 90 kJ of heat at constant pressure while 20 kJ of work is done on it. The system is brought to the original state by an adiabatic process. The initial internal energy is 100 kJ. Then what is the quantity of work transfer during the process?a)30 kJb)25 kJc)20 kJd)15 kJCorrect answer is option 'D'. Can you explain this answer? for Mechanical Engineering 2024 is part of Mechanical Engineering preparation. The Question and answers have been prepared according to the Mechanical Engineering exam syllabus. Information about 85 kJ of heat is supplied to a closed system at constant volume. During the next process, the system rejects 90 kJ of heat at constant pressure while 20 kJ of work is done on it. The system is brought to the original state by an adiabatic process. The initial internal energy is 100 kJ. Then what is the quantity of work transfer during the process?a)30 kJb)25 kJc)20 kJd)15 kJCorrect answer is option 'D'. Can you explain this answer? covers all topics & solutions for Mechanical Engineering 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for 85 kJ of heat is supplied to a closed system at constant volume. During the next process, the system rejects 90 kJ of heat at constant pressure while 20 kJ of work is done on it. The system is brought to the original state by an adiabatic process. The initial internal energy is 100 kJ. Then what is the quantity of work transfer during the process?a)30 kJb)25 kJc)20 kJd)15 kJCorrect answer is option 'D'. Can you explain this answer?.
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