Theory & Safety第 110 / 120 题
A 20-ohm resistor and a 30-ohm resistor are connected in parallel. What is the total resistance?
a.50 ohms
b.12 ohms
c.25 ohms
d.10 ohms
解析
For two resistors in parallel, R total = (R1 x R2) / (R1 + R2) = (20 x 30) / 50 = 600 / 50 = 12 ohms. The 50-ohm answer adds them as if they were in series, and 25 ohms averages them, but total parallel resistance is always less than the smallest branch resistance.
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