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Two 10 ohm resistors are wired in parallel. What is the total resistance?

5 ohms. Parallel total is always lower than the smallest branch.

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  1. 10 ohms
  2. 5 ohms ✔
  3. 20 ohms

Why: Adding a second path gives current more room to flow, so total resistance drops. Two equal resistors in parallel give half the value of one.

Huh, didn't know that: OpenStax notes a big motor's current can cause an IR drop in the wires, which is why lights dim when it starts.

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References

Answer: 5 ohms. Adding a second path gives current more room to flow, so total resistance drops. Two equal resistors in parallel give half the value of one.

  1. OpenStax College Physics 2e, 21.1 Resistors in Series and Parallel openstax.org/books/college-physics-2e/pages/21-1-resistors-in-series-and-parallel
    and so the total resistance is lower.
    Checked 2026-10-10.

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