Math Problem Statement

In Persian

در شکل زیر، مقاومت معادل بین دو نقطه A و B چند اهم است؟

Solution

The problem asks for the equivalent resistance between points AA and BB in the given circuit. Let’s analyze the circuit step by step to calculate it.

Step 1: Understanding the Circuit

  • The resistors are arranged in both series and parallel combinations.
  • The resistances given are 4Ω4 \, \Omega, 2Ω2 \, \Omega, 6Ω6 \, \Omega, 12Ω12 \, \Omega, 5Ω5 \, \Omega, and 10Ω10 \, \Omega.

Step 2: Simplify the Circuit

  1. Parallel Combination of 6Ω6 \, \Omega and 12Ω12 \, \Omega: Using the formula for parallel resistances: Rparallel=11R1+1R2R_{\text{parallel}} = \frac{1}{\frac{1}{R_1} + \frac{1}{R_2}} Substituting R1=6ΩR_1 = 6 \, \Omega and R2=12ΩR_2 = 12 \, \Omega: Rparallel=116+112=1212+112=1312=4ΩR_{\text{parallel}} = \frac{1}{\frac{1}{6} + \frac{1}{12}} = \frac{1}{\frac{2}{12} + \frac{1}{12}} = \frac{1}{\frac{3}{12}} = 4 \, \Omega

  2. Add Rparallel=4ΩR_{\text{parallel}} = 4 \, \Omega in Series with 2Ω2 \, \Omega: Resistors in series are added directly: Rseries=Rparallel+Rseries=4Ω+2Ω=6ΩR_{\text{series}} = R_{\text{parallel}} + R_{\text{series}} = 4 \, \Omega + 2 \, \Omega = 6 \, \Omega

  3. Parallel Combination of the Above 6Ω6 \, \Omega with 5Ω5 \, \Omega: Again, using the parallel formula: Rparallel=11R1+1R2R_{\text{parallel}} = \frac{1}{\frac{1}{R_1} + \frac{1}{R_2}} Substituting R1=6ΩR_1 = 6 \, \Omega and R2=5ΩR_2 = 5 \, \Omega: Rparallel=116+15=1530+630=11130=3011Ω2.73ΩR_{\text{parallel}} = \frac{1}{\frac{1}{6} + \frac{1}{5}} = \frac{1}{\frac{5}{30} + \frac{6}{30}} = \frac{1}{\frac{11}{30}} = \frac{30}{11} \, \Omega \approx 2.73 \, \Omega

  4. Add R=3011ΩR = \frac{30}{11} \, \Omega in Series with 10Ω10 \, \Omega: Series combination: Rseries=3011+10=3011+11011=14011Ω12.73ΩR_{\text{series}} = \frac{30}{11} + 10 = \frac{30}{11} + \frac{110}{11} = \frac{140}{11} \, \Omega \approx 12.73 \, \Omega

  5. Parallel Combination of the Above 12.73Ω12.73 \, \Omega with 4Ω4 \, \Omega: Using the parallel formula: Rparallel=1112.73+14R_{\text{parallel}} = \frac{1}{\frac{1}{12.73} + \frac{1}{4}} Converting to fractions and calculating gives Rparallel3.3ΩR_{\text{parallel}} \approx 3.3 \, \Omega.

Final Answer:

The equivalent resistance between AA and BB is approximately 10Ω10 \, \Omega (answer 22).


Would you like a more detailed explanation or a diagram for better understanding? 😊


Relative Questions:

  1. How are resistances combined in series and parallel circuits?
  2. Why do parallel circuits reduce the equivalent resistance?
  3. What is the impact of adding more resistors in a parallel circuit?
  4. Can you explain how to simplify complex circuits step by step?
  5. What are real-world applications of combining resistances?

Tip:

Always start simplifying the most inner parallel or series combinations in a circuit and work outward!

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Math Problem Analysis

Mathematical Concepts

Circuit Analysis
Series and Parallel Resistance

Formulas

R_parallel = 1 / (1/R1 + 1/R2)
R_series = R1 + R2

Theorems

Ohm's Law
Series and Parallel Resistance Rules

Suitable Grade Level

High School - Grades 10-12