Exam-style question
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If a potential divider has a total voltage of 15V and consists of two resistors of 3Ω and 7Ω, what is the voltage across the 3Ω resistor?.
- A.4.5V
- B.6V
- C.10.5V
- D.15V
Model answer
What a good answer should say
- 4.5V
Explanation
Why this works
Using V_out = V_total * (R1 / (R1 + R2)), where V_total = 15V, R1 = 3Ω, and R2 = 7Ω. Substituting gives V_out = 15 * (3 / (3 + 7)) = 15 * (3 / 10) = 4.5V.
Common mistake
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