Four resistors of 8 Ω each are connected in parallel, five such combinations are then connected in series. What is the total resistance?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 10 Ω
Resistors in parallel add as reciprocals, and resistors in series add directly. First find one parallel combination, then put five of them in series.
\( \displaystyle \frac{1}{R_p} = \frac{1}{8}+\frac{1}{8}+\frac{1}{8}+\frac{1}{8} = \frac{4}{8} \Rightarrow R_p = 2\,\Omega \)
\( R_{\text{total}} = 5\times R_p = 5\times2\,\Omega = 10\,\Omega \)