A resistor of 4 Ω carries a current of 5 A. What is the potential difference across it?
Answer and explanation
Correct answer: A. 20 V
- Step 1: Ohm's law: V = IR. Step 2. V = 5 × 4 = 20 V. Answer: 20 V. Why not the others: 0.8 V is what you get if you divide R by I. 1.25 V is what you get if you divide I by R. 9 V is what you get if you add the numbers.
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