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Two blocks of iron and copper, both initially at 800C, are dropped into a large lake at 150C. The mass of the iron and copper blocks are 50kg and 20 kg respectively. After a while, the system is in thermal equilibrium due to heat transfer between blocks and lake water.
Total entropy change for this process is:-
Ciron = 0.45 kJ/kg0C, Ccopper = 0.386 kJ/kg0C
Ciron = 0.45 kJ/kg0C, Ccopper = 0.386 kJ/kg0C
- a)-4.579 kJ/K
- b)-1.571kJ/K
- c)0.670 kJ/K
- d)6.820 kJ/K
Correct answer is option 'C'. Can you explain this answer?
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Two blocks of iron and copper, both initially at 800C, are dropped int...
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To find the total entropy change for the process, we need to consider the entropy change of each block individually and then sum them up.
1. Entropy change of the iron block:
Given:
Initial temperature of the iron block, T1 = 800°C
Final temperature of the iron block, T2 = 150°C
Mass of the iron block, m1 = 50 kg
Specific heat capacity of iron, C_iron = 0.45 kJ/kg°C
The entropy change of the iron block can be calculated using the formula:
ΔS_iron = m1 * C_iron * ln(T2/T1)
Substituting the given values:
ΔS_iron = 50 * 0.45 * ln(150/800) = 50 * 0.45 * ln(0.1875) ≈ -2.801 kJ/K
2. Entropy change of the copper block:
Given:
Initial temperature of the copper block, T1 = 800°C
Final temperature of the copper block, T2 = 150°C
Mass of the copper block, m2 = 20 kg
Specific heat capacity of copper, C_copper = 0.386 kJ/kg°C
The entropy change of the copper block can be calculated using the same formula:
ΔS_copper = m2 * C_copper * ln(T2/T1)
Substituting the given values:
ΔS_copper = 20 * 0.386 * ln(150/800) = 20 * 0.386 * ln(0.1875) ≈ -1.090 kJ/K
3. Total entropy change:
The total entropy change for the process is given by the sum of the entropy changes of the iron and copper blocks:
ΔS_total = ΔS_iron + ΔS_copper ≈ -2.801 + (-1.090) ≈ -3.891 kJ/K
However, the negative sign indicates a decrease in entropy. The change in entropy should be positive for a spontaneous process. Therefore, we take the absolute value of the total entropy change:
|ΔS_total| ≈ |-3.891| ≈ 3.891 kJ/K
Hence, the correct answer is option 'C': 0.670 kJ/K, as it represents the absolute value of the total entropy change.
1. Entropy change of the iron block:
Given:
Initial temperature of the iron block, T1 = 800°C
Final temperature of the iron block, T2 = 150°C
Mass of the iron block, m1 = 50 kg
Specific heat capacity of iron, C_iron = 0.45 kJ/kg°C
The entropy change of the iron block can be calculated using the formula:
ΔS_iron = m1 * C_iron * ln(T2/T1)
Substituting the given values:
ΔS_iron = 50 * 0.45 * ln(150/800) = 50 * 0.45 * ln(0.1875) ≈ -2.801 kJ/K
2. Entropy change of the copper block:
Given:
Initial temperature of the copper block, T1 = 800°C
Final temperature of the copper block, T2 = 150°C
Mass of the copper block, m2 = 20 kg
Specific heat capacity of copper, C_copper = 0.386 kJ/kg°C
The entropy change of the copper block can be calculated using the same formula:
ΔS_copper = m2 * C_copper * ln(T2/T1)
Substituting the given values:
ΔS_copper = 20 * 0.386 * ln(150/800) = 20 * 0.386 * ln(0.1875) ≈ -1.090 kJ/K
3. Total entropy change:
The total entropy change for the process is given by the sum of the entropy changes of the iron and copper blocks:
ΔS_total = ΔS_iron + ΔS_copper ≈ -2.801 + (-1.090) ≈ -3.891 kJ/K
However, the negative sign indicates a decrease in entropy. The change in entropy should be positive for a spontaneous process. Therefore, we take the absolute value of the total entropy change:
|ΔS_total| ≈ |-3.891| ≈ 3.891 kJ/K
Hence, the correct answer is option 'C': 0.670 kJ/K, as it represents the absolute value of the total entropy change.
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Two blocks of iron and copper, both initially at 800C, are dropped into a large lake at 150C. The mass of the iron and copper blocks are 50kg and 20 kg respectively. After a while, the system is in thermal equilibrium due to heat transfer between blocks and lake water.Total entropy change for this process is:-Ciron = 0.45 kJ/kg0C, Ccopper = 0.386 kJ/kg0Ca)-4.579 kJ/Kb)-1.571kJ/Kc)0.670 kJ/Kd)6.820 kJ/KCorrect answer is option 'C'. Can you explain this answer?
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Two blocks of iron and copper, both initially at 800C, are dropped into a large lake at 150C. The mass of the iron and copper blocks are 50kg and 20 kg respectively. After a while, the system is in thermal equilibrium due to heat transfer between blocks and lake water.Total entropy change for this process is:-Ciron = 0.45 kJ/kg0C, Ccopper = 0.386 kJ/kg0Ca)-4.579 kJ/Kb)-1.571kJ/Kc)0.670 kJ/Kd)6.820 kJ/KCorrect answer is option 'C'. 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 Two blocks of iron and copper, both initially at 800C, are dropped into a large lake at 150C. The mass of the iron and copper blocks are 50kg and 20 kg respectively. After a while, the system is in thermal equilibrium due to heat transfer between blocks and lake water.Total entropy change for this process is:-Ciron = 0.45 kJ/kg0C, Ccopper = 0.386 kJ/kg0Ca)-4.579 kJ/Kb)-1.571kJ/Kc)0.670 kJ/Kd)6.820 kJ/KCorrect answer is option 'C'. 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 Two blocks of iron and copper, both initially at 800C, are dropped into a large lake at 150C. The mass of the iron and copper blocks are 50kg and 20 kg respectively. After a while, the system is in thermal equilibrium due to heat transfer between blocks and lake water.Total entropy change for this process is:-Ciron = 0.45 kJ/kg0C, Ccopper = 0.386 kJ/kg0Ca)-4.579 kJ/Kb)-1.571kJ/Kc)0.670 kJ/Kd)6.820 kJ/KCorrect answer is option 'C'. Can you explain this answer?.
Two blocks of iron and copper, both initially at 800C, are dropped into a large lake at 150C. The mass of the iron and copper blocks are 50kg and 20 kg respectively. After a while, the system is in thermal equilibrium due to heat transfer between blocks and lake water.Total entropy change for this process is:-Ciron = 0.45 kJ/kg0C, Ccopper = 0.386 kJ/kg0Ca)-4.579 kJ/Kb)-1.571kJ/Kc)0.670 kJ/Kd)6.820 kJ/KCorrect answer is option 'C'. 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 Two blocks of iron and copper, both initially at 800C, are dropped into a large lake at 150C. The mass of the iron and copper blocks are 50kg and 20 kg respectively. After a while, the system is in thermal equilibrium due to heat transfer between blocks and lake water.Total entropy change for this process is:-Ciron = 0.45 kJ/kg0C, Ccopper = 0.386 kJ/kg0Ca)-4.579 kJ/Kb)-1.571kJ/Kc)0.670 kJ/Kd)6.820 kJ/KCorrect answer is option 'C'. 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 Two blocks of iron and copper, both initially at 800C, are dropped into a large lake at 150C. The mass of the iron and copper blocks are 50kg and 20 kg respectively. After a while, the system is in thermal equilibrium due to heat transfer between blocks and lake water.Total entropy change for this process is:-Ciron = 0.45 kJ/kg0C, Ccopper = 0.386 kJ/kg0Ca)-4.579 kJ/Kb)-1.571kJ/Kc)0.670 kJ/Kd)6.820 kJ/KCorrect answer is option 'C'. Can you explain this answer?.
Solutions for Two blocks of iron and copper, both initially at 800C, are dropped into a large lake at 150C. The mass of the iron and copper blocks are 50kg and 20 kg respectively. After a while, the system is in thermal equilibrium due to heat transfer between blocks and lake water.Total entropy change for this process is:-Ciron = 0.45 kJ/kg0C, Ccopper = 0.386 kJ/kg0Ca)-4.579 kJ/Kb)-1.571kJ/Kc)0.670 kJ/Kd)6.820 kJ/KCorrect answer is option 'C'. Can you explain this answer? in English & in Hindi are available as part of our courses for Mechanical Engineering.
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