CSCAPrep
Reviewed CSCA Physics question · Easy

两个电阻 R1 = 10 Ω 和 R2 = 20 Ω 串联后接在电压为30 V的电源两端。求通过 R1 的电流大小。

  1. 0.5 A
  2. 1 A
  3. 1.5 A
  4. 3 A
Show the answer and explanation

Correct answer

B. 1 A

Principle or equation

串联电路总电阻 R = R1 + R2，电流 I = U / R。

Why this answer is correct

总电阻 R = 10 + 20 = 30 Ω。电流 I = 30 / 30 = 1 A。串联电路中电流处处相等，所以通过 R1 的电流为1 A。

Example

若电压为60 V，则电流为2 A。

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