Question

Three resistances, each of 1 ohm, are joined in parallel. Three such combinations are put in series, then the resultant resistance will be

• A. 9 ohm
• B. 3 ohm
• C. 1 ohm
• D. $\frac{1}{3}ohm$

Answer 1

Answer: (C)

1 ohm

Answer 2

$\frac{1}{R} = \frac{1}{1} + \frac{1}{1} + \frac{1}{1} = \frac{3}{1}$ ⇒ $R = \frac{1}{3}ohm$

Now such three resistance are joined in series, hence total $R = \frac{1}{3} + \frac{1}{3} + \frac{1}{3} = 1ohm$