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Reviewed CSCA Physics question · Standard

两个电阻R1=6 Ω和R2=3 Ω并联，接在12 V的电源上（电源内阻不计）。求干路电流大小。

  1. 2 A
  2. 4 A
  3. 6 A
  4. 8 A
Show the answer and explanation

Correct answer

C. 6 A

Principle or equation

并联电阻总电阻公式：1/R总 = 1/R1 + 1/R2；欧姆定律：I = U/R。

Why this answer is correct

1/R总 = 1/6 + 1/3 = 1/2，所以R总=2 Ω。干路电流 I = 12/2 = 6 A。

Example

若R1=4 Ω，R2=4 Ω，并联总电阻为2 Ω，接在6 V上电流为3 A。

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