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Cocoleia
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Homework Statement
Homework Equations
The Attempt at a Solution
I attempted all of the parts:
Resistance, cross-sectional area of long coated wire
- Thread starter Cocoleia
- Start date
In summary, the conversation involved discussing a homework problem consisting of several parts (a)-(f). The person attempted all parts and was unsure about parts e and f. They asked for verification of their logic and were informed that part d was incorrect. They then corrected their mistake and asked if their subsequent steps were correct. Their method in part e was deemed correct, but they were advised to take the ratio instead of the product. In part f, they were told that they assumed incorrect values for the current density. They asked for guidance on how to calculate it without making this assumption. It was clarified that the problem was not a homework assignment, but rather practice for an exam. One solution proposed was to assume a potential and calculate the corresponding current flow
I attempted all of the parts:
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You have d wrong. The formula you quoted is not quite right.Cocoleia said:
- #3
Cocoleia
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Ah I see it should be 1/Req. If I change that, will the following steps be right assuming I use that value ?haruspex said:
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Your method in e) is right.Cocoleia said:
In f, you seem to have assumed all of I is in the inner wire when calculating the current density there.
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If you read posts 2 and 3, you'll see that d) was wrong, and this led to the wrong expression in e.kuruman said:
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Cocoleia
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How do I calculate it without assuming this? By the way, this isn't homework, I am just working on problems to prepare for an exam tomorrow.haruspex said:
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One way would be to suppose the potential applied to the wire is V and compute what current would flow in each component.Cocoleia said:
FAQ: Resistance, cross-sectional area of long coated wire
1. What is resistance?
Resistance is the measure of how difficult it is for electricity to flow through a material. It is represented by the letter R and measured in ohms (Ω).
2. How does the cross-sectional area of a long coated wire affect resistance?
The cross-sectional area of a wire refers to the size of the wire's cross-section. The larger the cross-sectional area, the lower the resistance will be, as there is more space for electrons to flow through the wire.
3. What is the relationship between resistance and wire length?
The longer the wire, the higher the resistance will be. This is because the electrons have to travel a longer distance, encountering more obstacles and increasing the overall resistance.
4. How does the type of coating on a wire affect its resistance?
The type of coating on a wire can affect its resistance in different ways. Some coatings, such as copper, have low resistance, while others, such as rubber, have higher resistance. The thickness of the coating can also impact resistance, as a thicker coating will provide more obstacles for electrons to pass through.
5. How can I calculate the resistance of a long coated wire?
You can calculate the resistance of a long coated wire by using the formula R = ρL/A, where R is resistance, ρ is the resistivity of the material, L is the length of the wire, and A is the cross-sectional area of the wire.