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Refrigerators X and Y are removing 1000 J of heat from the freezer. Refrigerator X is working between -5° C and 25° C and refrigerator Y is working between -20° C and 20 °C. Find efficiency of refrigerator X and Y?
  • a)
    20,2
  • b)
    7.9,6.5
  • c)
    9.8,7.3
  • d)
    8.9,7.3
Correct answer is option 'D'. Can you explain this answer?
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Refrigerators X and Y are removing 1000 J of heat from the freezer. Re...
We know that the efficiency of refrigeration for a refrigerator is T2 / T1 + T2
Where T1 is source temperature and T2 is sink temperature
For refrigerator X we have T1 = 298K and T2 = 268K
Hence the efficiency of refrigeration = 268 / 298 - 268
= 268 / 30
= 8.93
For refrigerator Y we have T1 = 293K and T2 = 253K
Hence the efficiency of refrigeration = 253 / 293 - 253
= 253 / 40
= 6.35
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Refrigerators X and Y are removing 1000 J of heat from the freezer. Re...
°C and 10°C, while refrigerator Y is working between -10°C and 5°C.

To determine which refrigerator is more efficient, we can calculate their coefficients of performance (COP). The COP is defined as the ratio of the heat removed from the freezer (Q_f) to the work done by the refrigerator (W).

For refrigerator X:
Temperature of the cold reservoir (T_c) = -5°C = 268 K
Temperature of the hot reservoir (T_h) = 10°C = 283 K

COP_X = Q_f / W_X
COP_X = Q_f / (Q_f - W)

For refrigerator Y:
Temperature of the cold reservoir (T_c) = -10°C = 263 K
Temperature of the hot reservoir (T_h) = 5°C = 278 K

COP_Y = Q_f / W_Y
COP_Y = Q_f / (Q_f - W)

Since both refrigerators are removing the same amount of heat (1000 J), we can compare their COPs by calculating the work done by each refrigerator.

For refrigerator X:
W_X = Q_f * (1 - (T_c / T_h))
W_X = 1000 J * (1 - (268 K / 283 K))
W_X = 1000 J * (1 - 0.946)
W_X = 1000 J * 0.054
W_X = 54 J

For refrigerator Y:
W_Y = Q_f * (1 - (T_c / T_h))
W_Y = 1000 J * (1 - (263 K / 278 K))
W_Y = 1000 J * (1 - 0.946)
W_Y = 1000 J * 0.054
W_Y = 54 J

Both refrigerators require the same amount of work (54 J) to remove 1000 J of heat from the freezer. Therefore, the COPs of both refrigerators are equal.

COP_X = Q_f / (Q_f - W_X)
COP_X = 1000 J / (1000 J - 54 J)
COP_X = 1000 J / 946 J
COP_X ≈ 1.06

COP_Y = Q_f / (Q_f - W_Y)
COP_Y = 1000 J / (1000 J - 54 J)
COP_Y = 1000 J / 946 J
COP_Y ≈ 1.06

Both refrigerators have a coefficient of performance of approximately 1.06, indicating that they are equally efficient in removing heat from the freezer.
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Attempt All sub parts from each question.If we turn on our electric oven, and it will warm up the room. Keeping the oven door open, the room gets warm even faster. This is obvious since the purpose of an oven is to make things hot. But the opposite is not true of a refrigerator. Running the refrigerator makes the room warmer. If the door is kept open, the room gets warm up even faster. The first rush of cold air may cool things down a little, but in the long run, the room will get warmer. To see why, we need to think of heat as energy and cold as a lack of energy. The stove produces heat, but the refrigerator can't actually produce cold. All the refrigerator does is move heat, or energy, from one place to another. As the food inside the refrigerator loses its heat or, in other words, gets colder that heat warms up the room A refrigerator is an open system that dispels heat from a closed space to a warmer area, usually in the room. By dispelling the heat from this area, it decreases the temperature inside, allowing food and other items to remain cool. Refrigerators appear to violate the second law of thermodynamics. But actually they do not. Physicists call this kind of system a "heat pump." According to the Second Law of Thermodynamics, heat always flows from hot to cold, and not in the other way around. A refrigerator causes heat to flow from cold to hot by inputting work, which cools the space inside it.It does this by following the steps below:• Work is inputted (Win) which compresses a coolant, increases its temperature above the room temperature.• Heat flows from coolant into the room (QH) reducing the temperature of the coolant.• The coolant expands and it cools down below the temperature inside the refrigerator.• Heat flows from the refrigerator to the coolant (QC) decreasing the temperature inside.So, the heat pump in refrigerator needs energy to run. So while it is busy in moving energy out of the refrigerator and into the room, it also draws more energy in the form of electricity. Since some of that energy is released as heat, the room gets warmer.For refrigerators, a manufacturer would want to make the area colder while doing as little work as possible. By doing little work to cool the appliance, the refrigerator can stay at the desired temperature while using less electricity. The number that describes this idea is known as the coefficient of performance, K, which is essentially a measure of efficiency.The higher this value is, the better the refrigerator, because it means that less work is being done to cool down the refrigerator.Q. Keeping the door of a refrigeration open the room temperature

Attempt All sub parts from each question.If we turn on our electric oven, and it will warm up the room. Keeping the oven door open, the room gets warm even faster. This is obvious since the purpose of an oven is to make things hot. But the opposite is not true of a refrigerator. Running the refrigerator makes the room warmer. If the door is kept open, the room gets warm up even faster. The first rush of cold air may cool things down a little, but in the long run, the room will get warmer. To see why, we need to think of heat as energy and cold as a lack of energy. The stove produces heat, but the refrigerator can't actually produce cold. All the refrigerator does is move heat, or energy, from one place to another. As the food inside the refrigerator loses its heat or, in other words, gets colder that heat warms up the room A refrigerator is an open system that dispels heat from a closed space to a warmer area, usually in the room. By dispelling the heat from this area, it decreases the temperature inside, allowing food and other items to remain cool. Refrigerators appear to violate the second law of thermodynamics. But actually they do not. Physicists call this kind of system a "heat pump." According to the Second Law of Thermodynamics, heat always flows from hot to cold, and not in the other way around. A refrigerator causes heat to flow from cold to hot by inputting work, which cools the space inside it.It does this by following the steps below:• Work is inputted (Win) which compresses a coolant, increases its temperature above the room temperature.• Heat flows from coolant into the room (QH) reducing the temperature of the coolant.• The coolant expands and it cools down below the temperature inside the refrigerator.• Heat flows from the refrigerator to the coolant (QC) decreasing the temperature inside.So, the heat pump in refrigerator needs energy to run. So while it is busy in moving energy out of the refrigerator and into the room, it also draws more energy in the form of electricity. Since some of that energy is released as heat, the room gets warmer.For refrigerators, a manufacturer would want to make the area colder while doing as little work as possible. By doing little work to cool the appliance, the refrigerator can stay at the desired temperature while using less electricity. The number that describes this idea is known as the coefficient of performance, K, which is essentially a measure of efficiency.The higher this value is, the better the refrigerator, because it means that less work is being done to cool down the refrigerator.Q. Performance of refrigerator is based on ............... law of thermodynamics.

Attempt All sub parts from each question.If we turn on our electric oven, and it will warm up the room. Keeping the oven door open, the room gets warm even faster. This is obvious since the purpose of an oven is to make things hot. But the opposite is not true of a refrigerator. Running the refrigerator makes the room warmer. If the door is kept open, the room gets warm up even faster. The first rush of cold air may cool things down a little, but in the long run, the room will get warmer. To see why, we need to think of heat as energy and cold as a lack of energy. The stove produces heat, but the refrigerator can't actually produce cold. All the refrigerator does is move heat, or energy, from one place to another. As the food inside the refrigerator loses its heat or, in other words, gets colder that heat warms up the room A refrigerator is an open system that dispels heat from a closed space to a warmer area, usually in the room. By dispelling the heat from this area, it decreases the temperature inside, allowing food and other items to remain cool. Refrigerators appear to violate the second law of thermodynamics. But actually they do not. Physicists call this kind of system a "heat pump." According to the Second Law of Thermodynamics, heat always flows from hot to cold, and not in the other way around. A refrigerator causes heat to flow from cold to hot by inputting work, which cools the space inside it.It does this by following the steps below:• Work is inputted (Win) which compresses a coolant, increases its temperature above the room temperature.• Heat flows from coolant into the room (QH) reducing the temperature of the coolant.• The coolant expands and it cools down below the temperature inside the refrigerator.• Heat flows from the refrigerator to the coolant (QC) decreasing the temperature inside.So, the heat pump in refrigerator needs energy to run. So while it is busy in moving energy out of the refrigerator and into the room, it also draws more energy in the form of electricity. Since some of that energy is released as heat, the room gets warmer.For refrigerators, a manufacturer would want to make the area colder while doing as little work as possible. By doing little work to cool the appliance, the refrigerator can stay at the desired temperature while using less electricity. The number that describes this idea is known as the coefficient of performance, K, which is essentially a measure of efficiency.The higher this value is, the better the refrigerator, because it means that less work is being done to cool down the refrigerator.Q. 2nd law of thermodynamics states

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Refrigerators X and Y are removing 1000 J of heat from the freezer. Refrigerator X is working between -5° C and 25° C and refrigerator Y is working between -20° C and 20 °C. Find efficiency of refrigerator X and Y?a)20,2b)7.9,6.5c)9.8,7.3d)8.9,7.3Correct answer is option 'D'. Can you explain this answer?
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Refrigerators X and Y are removing 1000 J of heat from the freezer. Refrigerator X is working between -5° C and 25° C and refrigerator Y is working between -20° C and 20 °C. Find efficiency of refrigerator X and Y?a)20,2b)7.9,6.5c)9.8,7.3d)8.9,7.3Correct answer is option 'D'. Can you explain this answer? for Class 11 2024 is part of Class 11 preparation. The Question and answers have been prepared according to the Class 11 exam syllabus. Information about Refrigerators X and Y are removing 1000 J of heat from the freezer. Refrigerator X is working between -5° C and 25° C and refrigerator Y is working between -20° C and 20 °C. Find efficiency of refrigerator X and Y?a)20,2b)7.9,6.5c)9.8,7.3d)8.9,7.3Correct answer is option 'D'. Can you explain this answer? covers all topics & solutions for Class 11 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Refrigerators X and Y are removing 1000 J of heat from the freezer. Refrigerator X is working between -5° C and 25° C and refrigerator Y is working between -20° C and 20 °C. Find efficiency of refrigerator X and Y?a)20,2b)7.9,6.5c)9.8,7.3d)8.9,7.3Correct answer is option 'D'. Can you explain this answer?.
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