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A copper wire of radius 0.5 mm is insulated with a sheathing of thickness 1 mm having a thermal conductivity of 0.5 W/mK. The outside surface convective heat transfer coefficient is 10 W/m²K. If the thickness of insulation sheathing is raised by 10 mm, then the electrical current-carrying capacity of the wire will
- a)increase
- b)decrease
- c)remain the same
- d)vary depending upon the electrical conductivity of the wire
Correct answer is option 'A'. Can you explain this answer?
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Verified Answer
A copper wire of radius 0.5 mm is insulated with a sheathing of thick...
rc = k/h = 0.5/10 = 0.05 = 50 mm
New radius =0.5+1+10 mm=11.5 mm
Since, radius is less then critical radius hence insulation provided will improve the heat loss and current carrying capacity will increase.
Most Upvoted Answer
A copper wire of radius 0.5 mm is insulated with a sheathing of thick...
Explanation:
To understand why the electrical current-carrying capacity of the wire will increase when the thickness of the insulation sheathing is raised by 10 mm, we need to consider the factors affecting the current-carrying capacity of a wire.
Factors affecting current-carrying capacity:
1. Temperature: The current-carrying capacity of a wire decreases as its temperature increases. This is because at higher temperatures, the resistance of the wire increases, leading to a decrease in the current-carrying capacity.
2. Heat dissipation: The ability of the wire to dissipate heat affects its current-carrying capacity. If the heat generated by the electrical current is not properly dissipated, it can cause the wire to overheat and reduce its current-carrying capacity.
Effect of insulation on current-carrying capacity:
Insulation is used to protect the wire and prevent the leakage of electrical current. However, insulation can also affect the wire's ability to dissipate heat. When the wire is insulated, the heat generated by the electrical current is trapped within the wire, leading to an increase in its temperature. This, in turn, reduces its current-carrying capacity.
Effect of increased insulation thickness:
When the thickness of the insulation sheathing is raised by 10 mm, it provides a thicker layer of insulation around the wire. This increases the distance between the wire and the outside surface, which improves the wire's ability to dissipate heat. The increased thickness of the insulation sheathing enhances the heat transfer from the wire to the surroundings.
Improved heat dissipation:
The improved heat dissipation due to the increased insulation thickness results in a lower temperature rise of the wire when electrical current passes through it. As a result, the resistance of the wire remains lower, allowing for a higher current-carrying capacity.
Conclusion:
Therefore, when the thickness of the insulation sheathing is raised by 10 mm, the electrical current-carrying capacity of the wire increases. This is because the increased insulation thickness improves the wire's ability to dissipate heat, resulting in a lower temperature rise and reduced resistance.
To understand why the electrical current-carrying capacity of the wire will increase when the thickness of the insulation sheathing is raised by 10 mm, we need to consider the factors affecting the current-carrying capacity of a wire.
Factors affecting current-carrying capacity:
1. Temperature: The current-carrying capacity of a wire decreases as its temperature increases. This is because at higher temperatures, the resistance of the wire increases, leading to a decrease in the current-carrying capacity.
2. Heat dissipation: The ability of the wire to dissipate heat affects its current-carrying capacity. If the heat generated by the electrical current is not properly dissipated, it can cause the wire to overheat and reduce its current-carrying capacity.
Effect of insulation on current-carrying capacity:
Insulation is used to protect the wire and prevent the leakage of electrical current. However, insulation can also affect the wire's ability to dissipate heat. When the wire is insulated, the heat generated by the electrical current is trapped within the wire, leading to an increase in its temperature. This, in turn, reduces its current-carrying capacity.
Effect of increased insulation thickness:
When the thickness of the insulation sheathing is raised by 10 mm, it provides a thicker layer of insulation around the wire. This increases the distance between the wire and the outside surface, which improves the wire's ability to dissipate heat. The increased thickness of the insulation sheathing enhances the heat transfer from the wire to the surroundings.
Improved heat dissipation:
The improved heat dissipation due to the increased insulation thickness results in a lower temperature rise of the wire when electrical current passes through it. As a result, the resistance of the wire remains lower, allowing for a higher current-carrying capacity.
Conclusion:
Therefore, when the thickness of the insulation sheathing is raised by 10 mm, the electrical current-carrying capacity of the wire increases. This is because the increased insulation thickness improves the wire's ability to dissipate heat, resulting in a lower temperature rise and reduced resistance.
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A copper wire of radius 0.5 mm is insulated with a sheathing of thickness 1 mm having a thermal conductivity of 0.5 W/mK. The outside surface convective heat transfer coefficient is 10 W/m²K. If the thickness of insulation sheathing is raised by 10 mm, then the electrical current-carrying capacity of the wire willa)increaseb)decreasec)remain the samed)vary depending upon the electrical conductivity of the wireCorrect answer is option 'A'. Can you explain this answer?
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A copper wire of radius 0.5 mm is insulated with a sheathing of thickness 1 mm having a thermal conductivity of 0.5 W/mK. The outside surface convective heat transfer coefficient is 10 W/m²K. If the thickness of insulation sheathing is raised by 10 mm, then the electrical current-carrying capacity of the wire willa)increaseb)decreasec)remain the samed)vary depending upon the electrical conductivity of the wireCorrect answer is option 'A'. Can you explain this answer? for Railways 2024 is part of Railways preparation. The Question and answers have been prepared according to the Railways exam syllabus. Information about A copper wire of radius 0.5 mm is insulated with a sheathing of thickness 1 mm having a thermal conductivity of 0.5 W/mK. The outside surface convective heat transfer coefficient is 10 W/m²K. If the thickness of insulation sheathing is raised by 10 mm, then the electrical current-carrying capacity of the wire willa)increaseb)decreasec)remain the samed)vary depending upon the electrical conductivity of the wireCorrect answer is option 'A'. Can you explain this answer? covers all topics & solutions for Railways 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A copper wire of radius 0.5 mm is insulated with a sheathing of thickness 1 mm having a thermal conductivity of 0.5 W/mK. The outside surface convective heat transfer coefficient is 10 W/m²K. If the thickness of insulation sheathing is raised by 10 mm, then the electrical current-carrying capacity of the wire willa)increaseb)decreasec)remain the samed)vary depending upon the electrical conductivity of the wireCorrect answer is option 'A'. Can you explain this answer?.
A copper wire of radius 0.5 mm is insulated with a sheathing of thickness 1 mm having a thermal conductivity of 0.5 W/mK. The outside surface convective heat transfer coefficient is 10 W/m²K. If the thickness of insulation sheathing is raised by 10 mm, then the electrical current-carrying capacity of the wire willa)increaseb)decreasec)remain the samed)vary depending upon the electrical conductivity of the wireCorrect answer is option 'A'. Can you explain this answer? for Railways 2024 is part of Railways preparation. The Question and answers have been prepared according to the Railways exam syllabus. Information about A copper wire of radius 0.5 mm is insulated with a sheathing of thickness 1 mm having a thermal conductivity of 0.5 W/mK. The outside surface convective heat transfer coefficient is 10 W/m²K. If the thickness of insulation sheathing is raised by 10 mm, then the electrical current-carrying capacity of the wire willa)increaseb)decreasec)remain the samed)vary depending upon the electrical conductivity of the wireCorrect answer is option 'A'. Can you explain this answer? covers all topics & solutions for Railways 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A copper wire of radius 0.5 mm is insulated with a sheathing of thickness 1 mm having a thermal conductivity of 0.5 W/mK. The outside surface convective heat transfer coefficient is 10 W/m²K. If the thickness of insulation sheathing is raised by 10 mm, then the electrical current-carrying capacity of the wire willa)increaseb)decreasec)remain the samed)vary depending upon the electrical conductivity of the wireCorrect answer is option 'A'. Can you explain this answer?.
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