Physics Olympiad question Electric circuit

In summary, the conversation revolves around a circuit with resistors of R ohms connected in different configurations. The question is to find the total resistance across points A and B. The conversation discusses finding series and parallel connections to simplify the circuit and reduce it to a single resistance. Through this process, the final answer is determined to be 5R/8 ohms.
  • #1
Hashiramasenju
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Homework Statement



In the Circuit(pic attached) the following resistor combination is found.
All the resistrs in the figure has resistance R ohms.
What is the total resistance across AB?

Homework Equations



V=IR
3. The attempt at a Solution
between point A and B there is only one resistor so i thought the answer is R
 

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  • #2
Hashiramasenju said:

Homework Statement



In the Circuit(pic attached) the following resistor combination is found.
All the resistrs in the figure has resistance R ohms.
What is the total resistance across AB?

Homework Equations



V=IR
3. The attempt at a Solution
between point A and B there is only one resistor so i thought the answer is R
No, there are multiple paths that current could take from A to B. Look for opportunities to combine series and parallel resistances to reduce the circuit complexity.

Your Relevant Equations should have included the formulas for combining resistances.:wink:
 
  • #3
gneill said:
No, there are multiple paths that current could take from A to B. Look for opportunities to combine series and parallel resistances to reduce the circuit complexity.

Your Relevant Equations should have included the formulas for combining resistances.:wink:
I could do the part i) I am stuck with the part ii)
 
  • #4
Show your work for part (i) and what you've tried for part (ii).
 
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  • #5
upload_2015-11-11_8-26-24.jpeg

This is for part i)
But for part ii) i seriously had no idea.
 
  • #6
Part i) work is good.

For part ii), can you not spot any series or parallel connections? What type of connection relationship do resistors AD and DC have?
 
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  • #7
yeah i noticed that resistors ad and dc are in series. Then resistors ac is parallel with ad&dc. so the only resistor left out is bc
 
  • #8
Hashiramasenju said:
yeah i noticed that resistors ad and dc are in series. Then resistors ac is parallel with ad&dc. so the only resistor left out is bc
Yes, so can you reduce the whole network down to a single resistance?
 
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  • #9
no. I really have no idea how to include resistance ab and bc in the circuit
 
  • #10
You've already identified that AD is in series with DC and so can be replaced by a single resistor, say "ADC". You also pointed out that this ADC is in parallel with AC, so that pair in turn can be replaced with a single resistor. What's the value of that resistor?
Fig1.png
Redraw the circuit with that new resistor in place and the remaining resistors.
 
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  • #11
I think i got it 5R/8
Thank you !
 
  • #12
Hashiramasenju said:
I think i got it 5R/8
Thank you !
Looks good.

You're welcome :smile:
 
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1. What is the Physics Olympiad Electric Circuit question about?

The Physics Olympiad Electric Circuit question is typically about solving complex problems related to electric circuits, which require knowledge and understanding of fundamental laws and principles in physics such as Ohm's law, Kirchhoff's laws, and circuit analysis techniques.

2. How do I prepare for the Physics Olympiad Electric Circuit question?

To prepare for the Physics Olympiad Electric Circuit question, you should have a strong understanding of basic electric circuit concepts and their applications. It is also important to practice solving problems and familiarize yourself with the different types of circuits and their characteristics. Additionally, studying past Olympiad questions and their solutions can be helpful in identifying patterns and improving problem-solving skills.

3. What are some common strategies for solving Physics Olympiad Electric Circuit questions?

Some common strategies for solving Physics Olympiad Electric Circuit questions include analyzing the circuit and identifying key components, applying relevant laws and principles, and breaking down the problem into smaller, more manageable parts. It is also important to double-check calculations and use appropriate units in your solutions.

4. Is it necessary to have advanced knowledge in mathematics for the Physics Olympiad Electric Circuit question?

While a strong understanding of basic mathematical concepts is necessary for solving Physics Olympiad Electric Circuit questions, advanced knowledge in mathematics is not usually required. However, some problems may involve complex algebraic equations and trigonometric functions, so it is helpful to have a good grasp of these concepts.

5. Are there any helpful resources for practicing Physics Olympiad Electric Circuit questions?

Yes, there are several resources available for practicing Physics Olympiad Electric Circuit questions. These include past Olympiad papers, study guides and textbooks, online forums and communities, and mock exams. It is also helpful to work with a study group or seek guidance from a mentor or teacher.

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