- #1
johnconnor
- 62
- 0
Algebra mistake? The answer is11.8ohm for (a).
Thank you!
Cambridge Physics Problems: Simple Electric Circuit
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Homework Help Overview
The discussion revolves around a problem related to simple electric circuits, specifically focusing on calculating resistance and voltage in a circuit involving a resistor and a rod. Participants are examining the relationships between current, voltage, and resistance as described by Ohm's law and Kirchhoff's rules.
Discussion Character
- Exploratory, Mathematical reasoning, Assumption checking
Approaches and Questions Raised
- Participants are questioning the accuracy of algebraic calculations and discussing the implications of current values on voltage and resistance. There are suggestions to reconsider the introduction of additional resistances and to clarify the definitions of voltage and current in the context of the circuit.
Discussion Status
The discussion is active, with participants providing guidance on how to approach the problem. Some are exploring different interpretations of the circuit's parameters, while others are identifying potential algebraic errors in previous calculations. There is no explicit consensus on the correct approach yet.
Contextual Notes
Participants are working within the constraints of a homework assignment, which may limit the information they can use or the assumptions they can make about the circuit components.
Algebra mistake? The answer is11.8ohm for (a).
Thank you!
- #2
azizlwl
- 1,066
- 10
What is V?
If V equal to supply voltage, then the maximum current in the circuit is 0.2A.
If V equal to supply voltage, then the maximum current in the circuit is 0.2A.
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- #3
TSny
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I would suggest that you avoid introducing the resistance of the rod.
For part (a), you know the current through both the resistor and the rod is 0.40 A. You have a formula that allows you to calculate the voltage across the rod if you know the current. So, see what you get for the voltage across the rod.
Kirchhoff says the sum of the voltages across the resistor and the rod must add to what?
So, you should be able to deduce the voltage across the resistor. If you know the voltage and the current for the resistor, how can you get the resistance of the resistor?
For part (a), you know the current through both the resistor and the rod is 0.40 A. You have a formula that allows you to calculate the voltage across the rod if you know the current. So, see what you get for the voltage across the rod.
Kirchhoff says the sum of the voltages across the resistor and the rod must add to what?
So, you should be able to deduce the voltage across the resistor. If you know the voltage and the current for the resistor, how can you get the resistance of the resistor?
- #4
TSny
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johnconnor said:
At the bottom of the first page of your notes, the denominator should be 15 - R rather than R - 15.